Article

Reduction of Intersex in a Wild Fish Population in Response to Major Municipal Wastewater Treatment Plant Upgrades

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Abstract

Intersex in fish downstream of municipal wastewater treatment plants (MWWTPs) is a global concern. Consistent high rates of intersex in male rainbow darter (Etheostoma caeruleum) have been reported for several years in the Grand River, in southern Ontario, Canada, in close proximity to two MWWTPs. The larger MWWTP (Kitchener) recently underwent upgrades that included the conversion from a carbonaceous activated sludge to nitrifying activated sludge treatment process. This created a unique opportunity to assess whether upgrades designed to improve effluent quality could also remediate the intersex previously observed in wild fish. Multiple years (2007-2012) of intersex data on male rainbow darter collected before the upgrades at sites associated with the MWWTP outfall were compared with intersex data collected in post-upgrade years (2013-2015). These upgrades resulted in a reduction from 70-100% intersex incidence (pre-upgrade) to <10% in post-upgrade years. Although the cause of intersex remains unknown, indicators of effluent quality including nutrients, pharmaceuticals, and estrogenicity improved in the effluent after the upgrades. This study demonstrated that investment in MWWTP upgrades improved effluent quality and was associated with an immediate change in biological responses in the receiving environment. This is an important finding considering the tremendous cost of wastewater infrastructure.

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... Two years after the Kitchener WWTP upgrades, there was no longer a significant reduction in 11KT and T production . Before the upgrades, 70-100% of male rainbow darter caught downstream of the Kitchener WWTP exhibited intersex, with a mean severity score of 2-3 (4 to >10 primary oocytes per subsample of a single testis) (Hicks et al., 2017a). By the third fall after the upgrades, intersex incidence decreased to 9-14% and the mean intersex score was less than one (fewer than 1-3 primary oocytes). ...
... Rainbow darter (Etheostoma caeruleum) are a small-bodied, benthic fish species found in riffle habitats and are widely distributed in the Grand River watershed . These fish are sexually dimorphic, short-lived (five years), reach sexual maturity at one year, and spawn in spring (Fuzzen et al., 2016;Hicks et al., 2017a). They have a small home range, confirmed through mark-recapture studies (Hicks and Servos, 2017), and are therefore an ideal sentinel species to examine the spatial effects of wastewater effluent. ...
... Intersex incidence and severity data were obtained for 2007 and 2010-2015 from Hicks et al. (2017a). Methods for fish collected from 2016 to 2019 followed those outlined in Hicks et al. (2017a) which targeted 25 male fish to be collected for intersex assessment from each site. ...
Article
Municipal wastewater treatment plant (WWTP) effluent is one of several point sources of contaminants (nutrients, pharmaceuticals, estrogens, etc.) which can lead to adverse responses in aquatic life. Studies of WWTP effluent impacts on rainbow darter (Etheostoma caeruleum) collected downstream of WWTPs in the Grand River, Ontario have reported disruption at multiple levels of biological organization, including altered vitellogenin gene expression, lower levels of in vitro steroid production, and high frequency of intersex. However, major upgrades have occurred at treatment plants in the central Grand River over the last decade. Treatment upgrades to the Waterloo WWTP were initiated in 2009 but due to construction delays, the upgrades came fully on-line in 2017/2018. Responses in rainbow darter have been followed at sites associated with the outfall consistently over this entire time period. The treatment plant upgrade resulted in nitrification of effluent, and once complete there was a major reduction in effluent ammonia, selected pharmaceuticals, and estrogenicity. This study compared several key responses in rainbow darter associated with the Waterloo WWTP outfall prior to and post upgrades. Stable isotopes signatures in fish were used to track exposure to effluent and changed dramatically over time, corresponding to the effluent quality. Disruptions in in vitro steroid production and intersex in the darters that had been identified prior to the upgrades were no longer statistically different from the upstream reference sites after the upgrades. Although annual variations in water temperature and flow can potentially mask or exacerbate the effects of the WWTP effluent, major capital investments in wastewater treatment targeted at improving effluent quality have corresponded with the reduction of adverse responses in fish in the receiving environment.
... An extended mussel extirpation zone (>7 km) was also observed downstream of the Kitchener WWTP even though a healthy population was immediately upstream (Gillis et al., 2017b). For other biota, increased rates of intersex in fish downstream of WWTPs and changes in water column and sediment prokaryote communities have been observed in this study area (Sonthiphand et al., 2013;Hicks et al., 2017a). In addition to assessing the microbiome of wild mussels, two supporting studies were conducted for method development; the first to confirm the location of the mussel digestive gland in the targeted species and the second to study the effect of sampling time on digestive gland microbiome sample integrity. ...
... REF2 is located within an urban area upstream of any significant municipal WWTPs but, like the further downstream sites, it receives road runoff. The Waterloo WWTP currently operates at partially nitrifying secondary treatment using conventional activated sludge (Hicks et al., 2017a;CIMA Canada Inc, 2018). Infrastructure investments including the conversion to nitrifying activated sludge have been made at the Kitchener WWTP (beginning in 2012) to improve effluent quality (Hicks et al., 2017a;CIMA Canada Inc, 2018). ...
... The Waterloo WWTP currently operates at partially nitrifying secondary treatment using conventional activated sludge (Hicks et al., 2017a;CIMA Canada Inc, 2018). Infrastructure investments including the conversion to nitrifying activated sludge have been made at the Kitchener WWTP (beginning in 2012) to improve effluent quality (Hicks et al., 2017a;CIMA Canada Inc, 2018). Despite some upgrades, the effluents of these two major WWTPs continue to be substantial sources of contaminants in the Grand River (Hicks et al., 2017a;. ...
Article
Gut microbial communities are vital for maintaining host health, and are sensitive to diet, environment, and chemical exposures. Wastewater treatment plants (WWTPs) release effluents containing antimicrobials, pharmaceuticals, and other contaminants that may negatively affect the gut microbiome of downstream organisms. This study investigated changes in the diversity and composition of the digestive gland microbiome of flutedshell mussels (Lasmigona costata) from upstream and downstream of two large (service >100,000) WWTPs. Mussel digestive gland microbiome was analyzed following the extraction, PCR amplification, and sequencing of bacterial DNA using the V3-V4 hypervariable regions of the 16 S rRNA gene. Bacterial alpha diversity decreased at sites downstream of the second WWTP and these sites were dissimilar in beta diversity from sites upstream and downstream of the first upstream WWTP. The microbiomes of mussels collected downstream of the first WWTP had increased relative abundances of Actinobacteria, Bacteroidetes, and Firmicutes, with a decrease in Cyanobacteria, compared to upstream mussels. Meanwhile, those collected downstream of the second WWTP increased in Proteobacteria and decreased in Actinobacteria, Bacteroidetes, and Tenericutes. Increased Proteobacteria has been linked to adverse effects in mammals, but their functions in mussels is currently unknown. Finally, effluent-derived bacteria were found in the microbiome of mussels downstream of both WWTPs but not in those from upstream. Overall, results show that the digestive gland microbiome of mussels collected upstream and downstream of WWTPs differed, which has implications for altered host health and the transport of WWTP-derived bacteria through aquatic ecosystems.
... Ten sites along the central Grand River spanning 60 km were sampled for fish in October 22-27, 2018 (Fig. 1); the sites were chosen based on their location relative to two large municipal secondary-conventional activated sludge treatment plants, the Waterloo and Kitchener WWTPs (Table 1, Fig. 1), that have been described in previous studies (Mehdi et al., 2017;Tetreault, 2012;Fuzzen et al., 2015;Fuzzen, 2016;Tetreault et al., 2013;Srikanthan, 2019). The Waterloo and Kitchener WWTPs serve approximately 98,000 and 219,000 people, respectively (Arlos et al., 2018b); upgrades have occurred recently at both plants and information on their operations are described in Hicks et al. (2017b). Our study is part of a larger program studying the impacts of wastewater effluents on rainbow darter (Tetreault, 2012;Tetreault et al., 2013;Fuzzen et al., 2015;Fuzzen, 2016;Hicks et al., 2017a;Hicks et al., 2017b). ...
... The Waterloo and Kitchener WWTPs serve approximately 98,000 and 219,000 people, respectively (Arlos et al., 2018b); upgrades have occurred recently at both plants and information on their operations are described in Hicks et al. (2017b). Our study is part of a larger program studying the impacts of wastewater effluents on rainbow darter (Tetreault, 2012;Tetreault et al., 2013;Fuzzen et al., 2015;Fuzzen, 2016;Hicks et al., 2017a;Hicks et al., 2017b). Several studies have characterized the chemical influences and water flow (Arlos et al., 2014, Arlos et al., 2018a, Arlos et al., 2018b, Srikanthan et al., 2019 at sites upstream and downstream of the Waterloo and Kitchener WWTPs. ...
... Several studies have characterized the chemical influences and water flow (Arlos et al., 2014, Arlos et al., 2018a, Arlos et al., 2018b, Srikanthan et al., 2019 at sites upstream and downstream of the Waterloo and Kitchener WWTPs. Furthermore, while there are numerous small WWTPs, agricultural inputs, and influences of large dams in the upper Grand River that alter nutrient cycling and aquatic community metabolism, the Waterloo and Kitchener WWTPs are major point source inputs of nutrients and contaminants (Loomer et al., 2015;Hicks et al., 2017a;Venkiteswaran et al., 2015), even after recent infrastructure upgrades (Hicks et al., 2017b). ...
Article
Municipal wastewater treatment plant (WWTP) effluent contains pharmaceuticals and personal care products known to affect fish health and reproduction. The microbiome is a community of bacteria integral in maintaining host health and is influenced by species, diet, and environment. This study investigated changes in the diversity and composition of the gut content microbiome of rainbow darter (Etheostoma caeruleum) at ten sites on the Grand River, Ontario, Canada. Gut contents were collected in Fall 2018 from rainbow darter at sites upstream and downstream of two municipal wastewater treatment plants (WWTPs; Waterloo and Kitchener). 16S rRNA genes were sequenced to determine the composition and diversity (alpha and beta) of microbial taxa present. Gut content bacterial diversity increased downstream of both WWTP outfalls; dominance of bacterial Amplicon Sequence Variants (ASVs) decreased compared to upstream fish. Fish collected at different sites had distinct bacterial communities, with upstream samples dominant in Proteobacteria and Firmicutes, and downstream samples increasingly abundant in Proteobacteria and Cyanobacteria. In mammals, increased abundance of Proteobacteria is indicative of microbial dysbiosis and has been linked to altered health outcomes, but this is not yet known for fish. This research indicates that the fish gut content microbiome was altered downstream of WWTP effluent outfalls and could lead to negative health outcomes.
... These data show that many European treatment plants (the older in particular) may need to be upgraded. In the USA, it has been shown that the modernization of the municipal wastewater treatment plants, which resulted in e.g. a reduced amount of estrogen released to the environment, led to a sharp decrease in the number of intersex cases of male rainbow darter (from 70% to 100% before modernization to less than 10% in the years after the modernization) (Hicks et al., 2017). This example shows that such AS -biological activated sludge treatment without nitrification,. ...
... One of the commonly reported negative effects of estrogens on fish is the feminization of many male species, which may lead to changes in primary and secondary sexual characteristics, and thus a reduction in the number of sperm cells produced or morphological changes (Dang and Kienzler, 2019;Filby et al., 2010;Jackson and Klerks, 2020;Karki et al., 2021;Martinez-Bengochea et al., 2020;Sumpter, 1995). There have also been many cases where the presence of estrogens in the environment caused the dominance of female individuals (Hill and Janz, 2003;Jackson and Klerks, 2020;Karki et al., 2021;Teta et al., 2018;Vajda et al., 2008) or the intensification of intersex (Hicks et al., 2017;Jobling et al., 2006) among many fish populations. Estrogens disrupt the production and egg quality of female freshwater and marine fish (Brian et al., 2007;Gutjahr-Gobell et al., 2006;Hill and Janz, 2003;Schäfers et al., 2007;Thorpe et al., 2009). ...
Article
Among the plethora of chemicals released into the environment, much attention is paid to endocrine disrupting compounds (EDCs). Natural estrogens, such as estrone (E1), 17β-estradiol (E2), estriol (E3) are excreted by humans as well as animals, and can enter the environment as a result of discharging domestic sewage and animal waste. These compounds can cause deleterious effects such as feminization, infertility and hermaphroditism in organisms that inhabit water bodies. This study provides an overview of the level of estrogen exposures in surface waters, groundwater and river sediments in European countries. The conducted review shows that estrogen concentrations were within the range of 0.1 ng L – 10 ng /L in the majority of the tested environmental samples. However, the authors of the study point out that there are still many unexplored areas and a limited amount of data that mainly concerns Eastern European countries. The study also analysed the factors that influence the increased emissions of estrogens to the environment, which may be helpful for identifying particularly polluted areas.
... Tissues, organs and systems are involved in vertebrate toxicokinetics: integument, respiratory and digestive organs are firstly subjected to pollutant exposure, due to their direct interface with the outside (Fatima et al., 2014;Alves et al., 2016;Salamat and Zarie, 2016;Strzyzewska et al., 2016); besides, nervous, immune, and endocrine systems are mostly studied (Kumari and Khare, 2018;Lonappan et al., 2016;Vogt et al., 2018;Xu et al., 2018;Gambardella et al., 2016;Adeogun et al., 2016;Hicks et al., 2017;Tulloch et al., 2016a). ...
... Moreover, several Authors (e.g. Koh et al., 2009;McAdam et al., 2010;Verlicchi et al., 2012;Hicks et al., 2017) evidenced the positive effect of an efficient nitrification on EDCs removal. ...
Article
This opinion paper focuses on the role of eco-toxicological tools in the assessment of possible impacts of emerging contaminants on the aquatic ecosystem, hence, on human health. Indeed, organic trace pollutants present in raw and treated wastewater are the pivot targets: a multidisciplinary approach allows defining the basic principles for managing this issue, from setting a proper monitoring campaign up to evaluating the optimal process treatment. Giving hints on trace pollutants fate and behaviour, attention is focused on the choice of the bioassay(s), by analysing the meaning of possible biological answers. Data interpretation and exploitation are detailed with the final goal of providing criteria in order to be able to select the best targeted treatment options. The manuscript deals with conventional and innovative analytical approaches for assessing toxicity, by reviewing laboratory and field assays; illustrative real scale and laboratory applications integrate and exemplify the proposed approach.
... Sources of endocrine disrupting compounds (EDCs) are widespread, but waste water treatment plants (WWTPs), pulp mills, and agricultural practices (e.g. crop and livestock production) are important, well studied sources of EDCs to the environment (Frye et al., 2012;Hicks et al., 2017;Pollock et al., 2010). Although EDCs have been documented extensively in natural systems, it is often unclear if their presence has demonstrable adverse effects to fish and wildlife (Mills and Chichester, 2005). ...
... That stated, in the current study perhaps the most notable observation was the continued decrease in the observation of intersex. Similar findings of decreased intersex prevalence were observed in rainbow darter (Etheostoma caeruleum) inhabiting the Grand River in Ontario, Canada following WWTP upgrades (Hicks et al., 2017). It is possible that perhaps unreported changes in land-use activity in the Missisquoi watershed have ameliorated the problem, and we observed recovery during the time of this investigation. ...
Article
A reconnaissance project completed in 2009 identified intersex and elevated plasma vitellogenin in male smallmouth bass inhabiting the Missisquoi River, VT. In an attempt to identify the presence and seasonality of putative endocrine disrupting chemicals or other factors associated with these observations, a comprehensive reevaluation was conducted between September 2012 and June 2014. Here, we collected smallmouth bass from three physically partitioned reaches along the river to measure biomarkers of estrogenic endocrine disruption in smallmouth bass. In addition, polar organic chemical integrative samples (POCIS) were deployed to identify specific chemicals associated with biological observations. We did not observe biological differences across reaches indicating the absence of clear point source contributions to the observation of intersex. Interestingly, intersex prevalence and severity decreased in a stepwise manner over the timespan of the project. Intersex decreased from 92.8% to 28.1%. The only significant predictor of intersex prevalence was year of capture, based on logistic regression analysis. The mixed model of fish length and year-of-capture best predicted intersex severity. Intersex severity was also significantly different across late summer and early spring collections indicating seasonal changes in this metric. Plasma vitellogenin and liver vitellogenin Aa transcript abundance in males did not indicate exposure to estrogenic endocrine disrupting chemicals at any of the four sample collections. Analysis of chemicals captured by the POCIS as well as results of screening discrete water samples or POCIS extracts did not indicate the contribution of appreciable estrogenic chemicals. It is possible that unreported changes in land-use activity have ameliorated the problem, and our observations indicate recovery. Regardless, this work clearly emphasizes that single, snap shot sampling for intersex may not yield representative data given that the manifestation of this condition within a population can change dramatically over time.
... In contrast, exposure of zebrafish to androgens such as fadrozole, can result in changes in sex ratios that are permanent (Huang et al., 2022). The possibility for a population to "recover" from a high prevalence of intersex individuals has important implications for ecological risk assessment and was recently demonstrated by a study that showed a significant reduction of this condition (from 70% to 10%) after an upgrade of a sewage treatment plant (Hicks et al., 2017). ...
... The results are somewhat surprising since when reviewing the literature, results indicating degradation of the gonads, whether in reduction of gonad tissue (Hicks, et al., 2017), delayed gametogenesis or histopathological damage to reproductive cells was also observed. Such pathologies are typically also observed by EDCs. ...
Preprint
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Word Count: 8986 Highlights • Chichester Harbour is exposed to a variety of pollutants from agriculture and sewage • Mussels were exposed to Chichester harbour via transplantation as a bioindicator • After 14 days mussels had increased gonad size and gametogenesis • It can be inferred that endocrine disrupting pollutants triggered these effects Layperson's summary Water around the world is becoming ever more polluted due to its economical relevance in a variety of industries, often being the site where waste products build up or are disposed. This affects not only on humans, but over 1 million aquatic species. It has been known for a long time that pollution is dangerous for the environment, however, only recently have studies identified their adverse impacts. Our aim was to observe the potential effect of pollutants on mussels in Chichester Harbour to aid our understanding of how pollutants work, their effect on mussels and their wider impact on aquatic populations. To measure this, mussels were exposed to the polluted Chichester Harbour for 14 days and compared to mussels kept in pollution free containers. The group exposed to Chichester Harbour was shown to have increased sexual tissue growth, which was most likely due to the pollutant levels. Discussion of the specific pollutants which could cause these effects are presented. This impacts research by showing the effects of a specific habitat on mussels, proposing several studies which could be used for further research. Abstract (150-word journal limit) Water pollution poses a major threat to aquatic life in the UK, with anthropogenic agricultural runoff and sewage waste being major contributors. Exogenous pollutants have potential to persist inside aquatic environments and build up inside organisms' tissues, however, localised area specific effects are still relatively unknown. Here we utilised a transplantation study to evaluate the impact of pollution in Chichester Harbour, UK, on blue mussel gonads. The exposure group was maintained in Chichester Harbour for 14 days whilst the control group was kept in sterile seawater. ImageJ and statistical analysis suggested that mussel gonad surface area (μm 2) was significantly larger when exposed to pollutants in Chichester Harbour, and light microscopy also observed higher rates of gametogenesis. Our results suggested a prevalence of endocrine disrupting chemicals in the harbour, originating from a variety of sources which interfered with the hypothalamic-pituitary-gonadal axis, by mimicking or providing steroid hormones such as oestrogen.
... The results are somewhat surprising since when reviewing the literature, results indicating degradation of the gonads, whether in reduction of gonad tissue (Hicks, et al., 2017), delayed gametogenesis or histopathological damage to reproductive cells was also observed. Such pathologies are typically also observed by EDCs. ...
Preprint
Full-text available
Word Count: 8986 Highlights • Chichester Harbour is exposed to a variety of pollutants from agriculture and sewage • Mussels were exposed to Chichester harbour via transplantation as a bioindicator • After 14 days mussels had increased gonad size and gametogenesis • It can be inferred that endocrine disrupting pollutants triggered these effects Layperson's summary Water around the world is becoming ever more polluted due to its economical relevance in a variety of industries, often being the site where waste products build up or are disposed. This affects not only on humans, but over 1 million aquatic species. It has been known for a long time that pollution is dangerous for the environment, however, only recently have studies identified their adverse impacts. Our aim was to observe the potential effect of pollutants on mussels in Chichester Harbour to aid our understanding of how pollutants work, their effect on mussels and their wider impact on aquatic populations. To measure this, mussels were exposed to the polluted Chichester Harbour for 14 days and compared to mussels kept in pollution free containers. The group exposed to Chichester Harbour was shown to have increased sexual tissue growth, which was most likely due to the pollutant levels. Discussion of the specific pollutants which could cause these effects are presented. This impacts research by showing the effects of a specific habitat on mussels, proposing several studies which could be used for further research. Abstract (150-word journal limit) Water pollution poses a major threat to aquatic life in the UK, with anthropogenic agricultural runoff and sewage waste being major contributors. Exogenous pollutants have potential to persist inside aquatic environments and build up inside organisms' tissues, however, localised area specific effects are still relatively unknown. Here we utilised a transplantation study to evaluate the impact of pollution in Chichester Harbour, UK, on blue mussel gonads. The exposure group was maintained in Chichester Harbour for 14 days whilst the control group was kept in sterile seawater. ImageJ and statistical analysis suggested that mussel gonad surface area (μm 2) was significantly larger when exposed to pollutants in Chichester Harbour, and light microscopy also observed higher rates of gametogenesis. Our results suggested a prevalence of endocrine disrupting chemicals in the harbour, originating from a variety of sources which interfered with the hypothalamic-pituitary-gonadal axis, by mimicking or providing steroid hormones such as oestrogen.
... The environmental occurrence of BC downstream from waste-water treatment plant (WWTP) outfalls have been shown to adversely affect fish health (Vajda et al., 2008;Corcoran et al., 2010;Barber et al., 2011;Jorgenson et al., 2018;Meador et al., 2018). In other cases, enhancements in treatment plant operations have been shown to remove nutrients and BC and improve conditions for fish Völker et al., 2016;Hicks et al., 2016;Marjan et al., 2017). ...
Article
Long-term (2010-19) water-quality monitoring on the Colorado River downstream from Moab Utah indicated the persistent presence of Bioactive Chemicals (BC), such as pesticides and pharmaceuticals. This stream reach near Canyonlands National Park provides critical habitat for federally endangered species. The Moab wastewater treatment plant (WWTP) outfall discharges to the Colorado River and is the nearest potential point-source to this reach. The original WWTP was replaced in 2018. In 2016-19, a study was completed to determine if the new plant reduced BC input to the Colorado River at, and downstream from, the outfall. Water samples were collected before and after the plant replacement at sites upstream and downstream from the outfall. Samples were analyzed for as many as 243 pesticides, 109 pharmaceuticals, 20 hormones, 51 wastewater indicator chemicals, 20 metals, and 8 nutrients. BC concentrations, hazard quotients (HQs), and exposure activity ratios (EARs) were used to identify and prioritize contaminants for their potential to have adverse biological effects on the health of native and endangered wildlife. There were 22 BCE with HQs >1, mostly metals and hormones; and 23 BCE with EARs >0.1, mostly hormones and pharmaceuticals. Most high HQs or EARs were associated with samples collected at the WWTP outfall site prior to its replacement. Discharge from the new plant had reduced concentrations of nutrients, hormones, pharmaceuticals, and other BC. For example, all 16 of the hormones detected at the WWTP outfall site had maximum concentrations in samples collected prior to the WWTP replacement. The WWTP replacement had less effect on instream concentrations of metals and pesticides, BC whose sources are less directly tied to domestic wastewater. Study results indicate that improved WWTP technology can create substantial reductions in concentrations of non-regulated BC such as pharmaceuticals, in addition to regulated contaminants such as nutrients.
... However, these compounds can be removed by upgrades to wastewater treatment plants (WWTPs). In the Grand River of Ontario, a river draining to Lake Erie, wild populations of rainbow darter showed a substantial reduction in intersex individuals below WWTPs after upgrades to operational processes, with frequencies returning to reference conditions within a few years (Hicks et al., 2017). For many natural resource-reliant industries, technological innovation guided by increasing social awareness of environmental degradation has the potential to substantially reduce pollution (Musetta-Lambert et al., 2019). ...
... Thus, upgrades to WWTPs can result in substantial improvements in effluent quality. For example, following upgrades to the WWTP in Kitchener (ON, Canada) to include nitrifying activated sludge treatment (at a cost of approximately $350 M), the percent of intersex male darters (Etheostoma caeruleum) downstream of the outflow dropped from 70 to 100% prior to the upgrade, to < 10% following the upgrade (Hicks et al. 2017). Mussels have been reported to accumulate many pharmaceuticals (Gilroy et al. 2014(Gilroy et al. , 2017de Solla et al. 2016), and there is a need to assess the toxicity of pharmaceuticals to freshwater organisms, both individually and in mixtures. ...
Article
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Municipal wastewater effluent is one of the largest sources of pollution entering surface waters in the Laurentian Great Lakes. Exposure to wastewater effluent has been associated with impaired immune systems and induction of genotoxicity to aquatic animals. Due to habitat degradation and environmental pollution linked to industrial development and population growth, several regions of the Great Lakes have been designated Areas of Concern (AOCs). In this study, we assessed the effect of extracts of sewage influent, (treated) effluent and receiving surface waters from the Hamilton Harbour AOC and the Toronto and Region AOC (Ontario, Canada) on the phagocytic immune response of rainbow trout (Oncorhynchus mykiss) kidney leukocytes and the genotoxicity (DNA strand breaks) of these extracts on freshwater mussel (Eurynia dilatata) hemocytes. We identified and quantified numerous chemicals present in the various samples extracted for exposure. In freshwater mussels, extracts from Hamilton Harbour AOC induced DNA damage with the most frequency (12 out of 28 samples) regardless of sample type, reflecting past and present industrial activities. In contrast, extracts from Toronto and Region AOC induced DNA damage infrequently (2 out of 32 (summer) and 5 out of 32 (fall) samples, respectively) and from different WWTPs at different times. None of the extracts induced any significant effect on phagocytosis of rainbow trout kidney leukocytes. The present study indicates that despite overall improvements to effluent quality, treatment of influent by WWTPs may not result in a corresponding improvement of the genotoxicity of effluents. In vitro bioassays are useful and cost-effective rapid-screening tools for preliminary assessments of contamination of aquatic ecosystems.
... The ability of partially treated municipal wastewater to disrupt the endocrine system of fish is not isolated the Grand River, and it has been observed across North America (Woodling et al. 2006;Vajda et al. 2008Vajda et al. , 2011Writer et al. 2010;Barber et al. 2011Barber et al. , 2015. However, other studies are showing that tertiary and other advanced forms of municipal wastewater treatment can remove many compounds contributing to endocrine disruption in fish (Barber et al. 2012;Baynes et al. 2012;Hicks et al. 2017). The challenge now is to implement these higher levels of treatment at municipal wastewater treatment facilities across North America. ...
Article
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Numerous anthropogenic factors, historical and contemporary, have contributed to declines in the abundance and diversity of freshwater fishes in North America. When Europeans first set foot on this continent some five hundred years ago, the environment was ineradicably changed. Settlers brought with them diseases, animals, and plants via the Columbian Exchange, from the old world to the new, facilitating a process of biological globalization. Invasive species were thus introduced into the Americas, displacing native inhabitants. Timber was felled for ship building and provisioning for agriculture, resulting in a mass land conversion for the purposes of crop cultivation. As European colonization expanded, landscapes were further modified to mitigate against floods and droughts via the building of dams and levees. Resources have been exploited, and native populations have been overfished to the point of collapse. The resultant population explosion has also resulted in wide-spread pollution of aquatic resources, particularly following the industrial and agricultural revolutions. Collectively, these activities have influenced the climate and the climate, in turn, has exacerbated the effects of these activities. Thus, the anthropogenic fingerprints are undeniable, but relatively speaking, which of these transformative factors has contributed most significantly to the decline of freshwater fishes in North America? This manuscript attempts to address this question by comparing and contrasting the preeminent drivers contributing to freshwater fish declines in this region in order to provide context and perspective. Ultimately, an evaluation of the available data makes clear that habitat loss, obstruction of streams and rivers, invasive species, overexploitation, and eutrophication are the most important drivers contributing to freshwater fish declines in North America. However, pesticides remain a dominant causal narrative in the popular media, despite technological advancements in pesticide development and regulation. Transitioning from organochlorines to organophosphates/carbamates, to pyrethroids and ultimately to the neonicotinoids, toxicity and bioaccumulation potential of pesticides have all steadily decreased over time. Concomitantly, regulatory frameworks designed to assess corresponding pesticide risks in Canada and the USA have become increasingly more stringent and intensive. Yet, comparatively, habitat loss continues unabated as agricultural land is ceded to the frontier of urban development, globalized commerce continues to introduce invasive species into North America, permanent barriers in the form of dams and levees remain intact, fish are still being extracted from native habitats (commercially and otherwise), and the climate continues to change. How then should we make sense of all these contributing factors? Here, we attempt to address this issue.
... Male fishes inhabiting xenoestrogen-contaminated water bodies exhibit increased levels of plasma Vtg (Bahamonde et al., 2015a(Bahamonde et al., , 2015bFlammarion et al., 2000;Harries et al., 1997;Hashimoto et al., 2000;Jobling et al., 1998Jobling et al., , 2002aJobling et al., , 2002bJohnson et al., 2008;Lavado et al., 2004;McGee et al., 2012;Orlando et al., 1999;Purdom et al., 1994;Sardi et al., 2015;Stansley & Washuta, 2007). Further, a positive correlation has been noticed between level of plasma Vtg and concentration of xenoestrogen in water bodies (Adeogun et al., 2016;Allen et al., 1999;Blazer et al., 2014;Feist et al., 2005;Hecker et al., 2002;Hicks et al., 2017;Jobling et al., 2006;McMaster, 2001;Vajda et al., 2008). A similar inference has been drawn in male fishes in which increase in Vtg is seen inversely proportional to the distance of their habitat from the effluent discharge site (Bahamonde, Fuzzen, et al., 2015;Blazer et al., 2014;Harries et al., 1997). ...
Article
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Among vertebrates, teleosts display a wide array of sex determination and differentiation mechanisms ranging from chromosomal sex determination on one end of the spectrum to environmental sex determination on the other end. However, the interplay of both these mechanisms is also not uncommon. Several gonochoristic fishes exhibit gonadal plasticity often resulting in sex reversal. The major manipulation of sex differentiation in teleost is affected by sex steroids. In this context, the increasing contamination of aquatic ecosystems by estrogen-like compounds, commonly known as xenoestrogens, is of major concern. This often leads to deleterious effects on the reproductive success of fish and thereby adversely impacts aquatic biodiversity. In the present review, we have focused on impact of xenoestrogen at different levels of the reproductive system influencing not only gonadal differentiation in teleosts but also their reproductive functions. The review would also explore the mitigation strategies and regulations in place for aquatic xenoestrogen management.
... A key response also noted in the male darters to municipal effluent exposure was the induction VTG. Recent upgrades in sewage treatment within the watershed have resulted in reduced prevalence of intersex in the darters (Hicks et al., 2017). In other studies, upgrades of the wastewater treatment plant in Boulder Colorado, resulted in improved removal efficiency for many EDCs, particularly 17β-estradiol and estrone, and fathead minnow exposed to the post upgrade effluent showed reduced endocrine disruption relative to pre-upgrade conditions (Barber et al., 2012). ...
Article
Endocrine disrupting chemicals (EDCs) are ubiquitous in aquatic and terrestrial environments. The main objective of this review was to summarize the current knowledge of the impacts of EDCs on reproductive success in wildlife and humans. The examples selected often include a retrospective assessment of the knowledge of reproductive impacts over time to discern how the effects of EDCs have changed over the last several decades. Collectively, the evidence summarized here within reinforce the concept that reproduction in wildlife and humans is negatively impacted by anthropogenic chemicals, with several altering endocrine system function. These observations of chemicals interfering with different aspects of the reproductive endocrine axis are particularly pronounced for aquatic species and are often corroborated by laboratory-based experiments (i.e. fish, amphibians, birds). Noteworthy, many of these same indicators are also observed in epidemiological studies in mammalian wildlife and humans. Given the vast array of reproductive strategies used by animals, it is perhaps not surprising that no single disrupted target is predictive of reproductive effects. Nevertheless, there are some general features of the endocrine control of reproduction, and in particular, the critical role that steroid hormones play in these processes that confer a high degree of susceptibility to environmental chemicals. New research is needed on the implications of chemical exposures during development and the potential for long-term reproductive effects. Future emphasis on field-based observations that can form the basis of more deliberate, extensive, and long-term population level studies to monitor contaminant effects, including adverse effects on the endocrine system, are key to addressing these knowledge gaps.
... Similar results were described in studies performed by Jobling et al., [64] where estrogens (E1, E2, and EE2) have impacted population of roach (Rutilus rutilus) in British rivers. Results presented by Hicks et al. [65] where upgrades to the municipal wastewater treatment plant (Grand River, Canada) and as an effect lower the amount of estrogens in environment have led to rapid decline of intersex rainbow darter (Etheostoma caeruleum) males strongly correspond with those presented by Kidd and Jobling. On the other hand, in studies performed by Wang et al. [66] EE2 concentrations detected in Liaodong Bay (China) 0.42 ng/L, were too low to affect Wild Soiuy Mullets (Mugil soiuy) population. ...
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Nowadays, there is a growing interest in environmental pollution; however, knowledge about this aspect is growing at an insufficient pace. There are many potential sources of environmental con-tamination, including sex hormones—especially estrogens. The analyzed literature shows that es-trone (E1), estradiol (E2), estriol (E3), and synthetic ethinyloestradiol (EE2) are the most significant in terms of environmental impact. Potential sources of contamination are, among others, livestock farms, slaughterhouses, and large urban agglomerations. Estrogens occurring in the environment can negatively affect the organisms, such as animals, through phenomena such as feminization, dysregulation of natural processes related to reproduction, lowering the physiological condition of the organisms, disturbances in the regulation of both proapoptotic and anti-apoptotic processes, and even the occurrence of neoplastic processes thus drastically decreasing animal welfare. Un-fortunately, the amount of research conducted on the negative consequences of their impact on animal organisms is many times smaller than that of humans, despite the great richness and di-versity of the fauna. Therefore, there is a need for further research to help fill the gaps in our knowledge.
... Rainbow darter (Etheostoma caeruleum) are a small-bodied, freshwater, benthic and carnivorous fish found in northeastern North America, and known to have a small home range of approximately 5.0 m (Hicks et al., 2017b), making them valuable as a sentinel species in field studies. In particular, this species has been used for field studies of WWTP effluents (Fuzzen, 2016;Fuzzen et al., 2015;Hicks et al., 2017a;Mehdi et al., 2017;Robinson et al., 2016;Tetreault et al., 2012Tetreault et al., , 2014, including one study of their gut microbiome (Restivo et al., 2021). The rainbow darter is amenable to laboratory rearing and holding (Fuzzen, 2016;Dhakal, 2017;Mehdi et al., 2017;Turner and Bucking, 2019) and has been used to examine the effects of diet on the gut microbiome (Dhakal, 2017, Turner andBucking, 2019), making them ideal for the present study. ...
Article
An increasing number of laboratory studies are showing that environmental stressors and diet affect the fish gut microbiome. However, the application of these results to wild populations is uncertain as little is known about how the gut microbiome shifts when fish are transitioned from the field to the laboratory. To assess this, intestinal contents (i.e. digesta) of wild-caught rainbow darter (Etheostoma caeruleum) were sampled in the field and in the lab after 14- and 42-days acclimation. In addition, from days 15–42 some fish were exposed to waterborne triclosan, an antimicrobial found in aquatic ecosystems, or to dilutions of municipal wastewater effluents, to determine how these stressors affect the bacterial communities of gut contents. 16S rRNA gene amplicon sequencing was used to determine microbial community composition, alpha, and beta diversity present in the fish gut contents. In total, there was 8,074,658 reads and 11,853 amplicon sequence variants (ASVs) identified. The gut contents of wild fish were dominant in both Proteobacteria (35%) and Firmicutes (27%), while lab fish were dominant in Firmicutes (37–47%) and had lower alpha diversity. Wild fish had greater ASVs per sample (423-1304) compared to lab fish (19-685). Similarly, the beta-diversity of these bacterial communities differed between field and lab control fish; control fish were distinct from the 10% wastewater effluent and 100 ng/L TCS treatment groups. Results indicate that the gut microbiome of wild fish changes with the transition to laboratory environments; hence, prolonged acclimation to new settings may be required to achieve a stable gut content microbiome in wild-caught fish. Research is required to understand the length of time required to reach a stable fish gut microbiome.
... It is worth noting that environmental decision making is not always straightforward even when cost and political considerations are excluded. For example, enhanced WWTP N oxidation without denitrification may mitigate cHABs and accelerate degradation of numerous pharmaceuticals (Hicks et al. 2017), but both oxidation and denitrification (N removal) can increase emissions of N 2 O, a greenhouse gas and major ozonedepleting substance (Kampschreur et al. 2009, Ravishankara et al. 2009, Law et al. 2012). On the other hand, adding denitrification to remove N may provide benefits that outweigh cHAB mitigation, such as lower production of nitrogenous cyanotoxins (Downing et al. 2005, Orihel et al. 2012, Horst et al. 2014, Gobler et al. 2016, smaller risk of toxic levels of ammonia and nitrate in surface waters, and improvement of hypoxia in marine coastal zones (Glibert et al. 2006, Paerl 2009). ...
Article
Molot LA, Schiff SL, Venkiteswaran JJ, Baulch HM, Higgins SN, Zastepa A, Verschoor MJ, Walters D. 2021. Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management. Lake Reserv Manage. XX:XXX-XXX. Field observations and experimental manipulations with different oxidizing agents including nitrate demonstrate that high sediment redox prevents cyanobacteria blooms in eutrophic freshwaters. Conversely, low sediment redox caused by depletion of dissolved oxygen and nitrate allows blooms to form. This explains why bloom risk increases with phosphorus levels: Higher productivity increases the spatial and temporal extent of low sediment redox. The intermediate link between low redox and cyanobacteria blooms appears to be internal loading of ferrous iron (Fe²⁺) from reduced sediments with diffusion to depths accessible to migrating cyanobacteria, providing a source for their high iron demand. Regardless of whether Fe²⁺ release is the intermediate link, the concept of “low sediment redox as promoter” has major potential to improve bloom management if managers consider the impact of their nutrient management choices, nutrient targets, and in-lake methods on sediment redox. Phosphorus input targets can be adjusted as climate change alters the extent of anoxia, and short-term bloom prediction models that incorporate the sediment redox concept could predict onset of blooms earlier than current models that depend on detection of photosynthetic pigments associated with blooms.
... Our hypothesis was that the restored streams have lower levels of nutrients and EEDCs than the unrestored streams, although both restored and unrestored sub-watersheds have the potential to receive the same inputs. The effect of upgrades of WWTPs on EEDCs and nutrient reduction was evaluated by examining changes across wastewater treatment profiles of a WWTP (Barber et al., 2012;Hicks et al., 2017), as well as their upstream-downstream changes in chemical concentrations in receiving waters (Ciparis et al., 2012). Moreover, we compared nutrient and EEDCs in a CSO with those collected from WWTP effluents to assess potential effects of replacing aging CSO systems. ...
Article
We evaluate the impacts of different nutrient management strategies on the potential for co-managing estrogens and nutrients in environmental waters of the Potomac watershed of the Chesapeake Bay. These potential co-management approaches represent agricultural and urban runoff, wastewater treatment plant effluent, and combined sewer overflow replacements. Twelve estrogenic compounds and their metabolites were analysed by gas chromatography–mass spectrometry. Estrogenic activity (E2Eq) was measured by in vitro bioassay. We detected estrone E1 (0.05–6.97 ng L⁻¹) and estriol E3 (below detection-8.13 ng L⁻¹) and one conjugated estrogen (estrone-3-sulfate E1-3S; below detection-8.13 ng L⁻¹). E1 was widely distributed and positively correlated with E2Eq, water temperature, and dissolved organic carbon (DOC). Among nonpoint sources, E2Eq, and concentrations of E1, soluble reactive phosphorus (SRP) and total dissolved nitrogen (TDN) decreased by 51–61%, 77–82%, 62–64%, 4–16% in restored urban and agricultural streams with best management practices (BMPs) relative to unrestored streams without BMPs. In a wastewater treatment plant (Blue Plains WWTP), >94% of E1, E1-3S, E3, E2Eq and TDN were removed while SRP increased by 305% during nitrification/denitrification as a part of advanced wastewater treatment. Consequently, E1 and TDN concentrations in WWTP effluents were comparable or even lower than those observed in the receiving stream or river waters, and the effects of wastewater discharges on downstream E1 and TDN concentrations were minor. Highest E2Eq value and concentrations of E1, E3, and TDN were detected in combined sewer overflow (CSO). This study suggests that WWTP upgrades with biological nutrient removal, CSO management, and certain agricultural and urban BMPs for nutrient controls have the potential to remove estrogens from point and nonpoint sources along with other contaminants in streams and rivers.
... In past studies, effects on reproduction, growth, sex ratios, metabolism, and molecular signatures have all been identified as maladaptive phenotypes in downstream locations from MWWTPs in this area, which were attributed to effluent exposure [3][4][5]. Rainbow darters downstream from the MWWTPs in the Grand River have experienced changes in gene expression, skewed sex ratios, altered gonad size, and intersex or feminized fish populations are found, largely due to the presence of EDCs [6,7]. Additionally, run-off from urban developments and intense agricultural areas, along with stormwater drainages, are other sources of contamination and water quality degradation [8,9]. ...
Article
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The effluent from municipal wastewater treatment plants is a major point source of contamination in Canadian waterways. The improvement of effluent quality to reduce contaminants, such as pharmaceuticals and personal care products, before being released into the environment is necessary to reduce the impacts on organisms that live in the river downstream. Here, we aimed to characterize the metabolic and gill physiological responses of rainbow (Etheostoma caeruleum), fantail (Etheostoma flabellare), and greenside (Etheostoma blennioides) darters to the effluent in the Grand River from the recently upgraded Waterloo municipal wastewater treatment plant. The routine metabolism of darters was not affected by effluent exposure, but some species had increased maximum metabolic rates, leading to an increased aerobic scope. The rainbow darter aerobic scope increased by 2.2 times and the fantail darter aerobic scope increased by 2.7 times compared to the reference site. Gill samples from effluent-exposed rainbow darters and greenside darters showed evidence of more pathologies and variations in morphology. These results suggest that darters can metabolically adjust to effluent-contaminated water and may also be adapting to the urban and agricultural inputs. The modification and damage to the gills provide a useful water quality indicator but does not necessarily reflect how well acclimated the species is to the environment due to a lack of evidence of poor fish health.
... River water was collected to assess the estrogenicity of the SAR at baseflow conditions. The mean in vitro EEQs for August/September and November sampling events were consistent with EEQs determined from previous studies evaluating the estrogenicity of the SAR and other effluent-dominated river systems (Hicks et al., 2017;Song et al., 2020;Vajda et al., 2008;Xie et al., 2004). EEQs ranged from <1 to 2.57 ng/L in effluent collected from Prado in April 2003 (Xie et al., 2004), and between 0.02 ng/L and 3.4 ng/L in sites located upstream and downstream of an effluent outfall in Boulder Creek in September 2003, respectively (Vajda et al., 2008). ...
Article
Estrogenically active compounds (EACs) in surface waters can disrupt the endocrine system of biota, raising concern for aquatic species. Concentrations of EACs are generally higher in effluent-dominated aquatic systems, such as California's Santa Ana River (SAR). Addressing estrogenicity of effluent-dominated waters is increasingly important due to both increasing urbanization and climate change. To this end, water samples were collected from multiple sites downstream of wastewater treatment plants (WWTPs) and intermittent points along the SAR during 2018–2019 and cell-based bioassays were used to determine estrogen receptor activity. During baseflow conditions, the highest estradiol equivalencies (EEQs) from all SAR water between summer (August and September) and fall (November) sampling events in 2018 were from Yorba Linda (EEQ = 1.36 ± 0.38 ng/L) and Prado (1.14 ± 0.13 ng/L), respectively. Water extracts in January 2019 following a major rainfall generally had higher EEQs with the highest EEQ of 10.0 ± 0.69 ng/L observed at Yorba Linda. During low flow conditions in November 2018, male Japanese medaka (Oryzias latipes) fish were exposed to SAR water to compare to cell bioassay responses and targeted analytical chemistry for 5 steroidal estrogens. Chemical-based EEQ correlations with in vitro EEQs were statistically significant. However, vitellogenin (vtg) mRNA expression in the livers of medaka exposed to SAR water was not significantly different compared to controls. These results indicate that seasonal variation and surface water runoff events influence estrogenic activity in the SAR and may induce estrogenic effects to native fish populations in wastewater-dominated streams in general.
... The synthetic hormone 17αethinylestradiol was demonstrated to have caused the collapse of a fish population at concentrations detected in the environment (Kidd et al. 2007). Hicks et al. (2017) reported decreased incidence of intersex in a population of rainbow darters downstream of a municipal sewage treatment facility, after plant upgrades, with corresponding decreases in the concentration of estrogens detected in the effluent. However, observed effects in invertebrates have not been as clear-cut, and questions remain as to whether these compounds have any hormonal action in molluscs (Scott 2012(Scott , 2013. ...
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The toxicity of endocrinologically active pharmaceuticals finasteride (FIN) and melengestrol acetate (MGA) was assessed in freshwater mussels, including acute (48 h) aqueous tests with glochidia from Lampsilis siliquoidea, sub-chronic (14 days) sediment tests with gravid female Lampsilis fasciola, and chronic (28 days) sediment tests with juvenile L. siliquoidea, and in chronic (42 days) sediment tests with the amphipod Hyalella azteca and the mayfly Hexagenia spp. Finasteride was not toxic in acute aqueous tests with L. siliquoidea glochidia (up to 23 mg/L), whereas significant toxicity to survival and burial ability was detected in chronic sediment tests with juvenile L. siliquoidea (chronic value (ChV, the geometric mean of LOEC and NOEC) = 58 mg/kg (1 mg/L)). Amphipods (survival, growth, reproduction, and sex ratio) and mayflies (growth) were similarly sensitive (ChV = 58 mg/kg (1 mg/L)). Melengestrol acetate was acutely toxic to L. siliquoidea glochidia at 4 mg/L in aqueous tests; in sediment tests, mayflies were the most sensitive species, with significant growth effects observed at 37 mg/kg (0.25 mg/L) (ChV = 21 mg/kg (0.1 mg/L)). Exposure to sublethal concentrations of FIN and MGA had no effect on the (luring and filtering) behaviour of gravid L. fasciola, or the viability of their brooding glochidia. Based on the limited number of measured environmental concentrations of both chemicals, and their projected concentrations, no direct effects are expected by these compounds individually on the invertebrates tested. However, organisms are exposed to contaminant mixtures in the aquatic environment, and thus, the effects of FIN and MGA as components of these mixtures require further investigation.
... The alarming increase in the detection of ovotestis, testiova, imposex and testicular oocyte conditions are observed among gonochoristic teleosts inhabiting chemically contaminated sites of the aquatic environment (Table 2). Furthermore, reports of intersexuality show either feminization (oocytes within testicular tissue) or masculinization (spermatogenic cells within the ovarian tissue) conditions among teleost fishes (Sardi et al. 2015a;Grilo and Rosa 2017;Hicks et al. 2017). The effects of intersexuality resulting from exposure to xenoestrogenic contaminants include delayed spermatogenesis and oogenesis in males and females, respectively (Bahamonde et al. 2015). ...
Article
Xenoestrogens mimic and interfere with natural functions of oestrogens and adversely affect fish reproduction. Pesticides, plastics, wastewaters and pharmaceuticals are sources of xenoestrogens, and are carried through surface runoffs to water bodies at concentration levels that are harmful to aquatic organisms. Fish absorb xenoestrogens through ingestion of contaminated food items, respiratory gills and dermal contact. Xenoestrogens bioaccumulate in fish tissues, eliciting various reproductive abnormalities, e.g. males may abnormally produce vitellogenins and present with reduced sperm counts, whereas females experience reduced fecundity and hatchability of eggs. Through the food web, xenoestrogens biomagnify in fish predators, e.g. seals and humans, which in turn risk suffering from reproductive malfunctions. Studies of adverse impact of xenoestrogens on fish have mainly been limited to developed countries, yet fish are a major food and trade commodity for developing sub-Saharan African countries. This review serves as a basis for research on adverse impacts of xenoestrogens on fish reproduction, and other consumers of aquatic organisms in Lake Victoria. The lake receives high levels of pollutants from untreated or poorly-treated domestic and industrial wastes and agro-chemicals. Control of xenoestrogens requires concerted effort from multistakeholders to undertake activities such as surveillance, advocacy, legislation and biodegradation to minimise their adverse impacts.
... Additionally, Cipoletti et al. (2019) reported delays in development and growth rate responses in larval and juvenile fathead minnows exposed to CECs present in the Maumee River. While the ecotoxic effects of many CECs and their potential impacts on ecosystems are poorly understood, there is growing evidence suggesting exposure to low concentrations of some of these chemicals and chemical mixtures have physiological effects on fish and other wildlife and can disrupt their endocrine and immune systems (Gonz alez et al., 2012;Jasinska et al., 2015;Hicks et al., 2017;Thomas et al., 2017;Cipoletti et al., 2019). In general these effects do not cause mortality and are not grossly observable in the individual animal, therefore they may be imperceptible until significant or catastrophic impairments to aquatic wildlife populations and communities are realized. ...
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Recent research suggests contaminants of emerging concern (CECs) are widespread and environmentally relevant concentrations can impact fishes. However, little is known about impacts of CECs to long-lived or rare species. The objective of this study was to characterize CEC concentrations in lake sturgeon serum and gametes. Blood serum was collected non-lethally from lake sturgeon (Acipenser fulvescens) at four lower Great Lakes basin sites: Detroit, upper Niagara, lower Niagara, and St. Lawrence rivers; additionally, gametes were collected from lake sturgeon in the St. Lawrence River. Samples were analyzed for pharmaceuticals and personal care products (PPCPs) and polybrominated diphenyl ethers (PBDEs). Overall, 44 different PPCPs were identified in serum and gamete samples across sites, with 22 PPCPs identified in at least 25% of serum samples and three PPCPs identified in 25% of gamete samples. PPCP concentrations in serum and gametes ranged from 0.00208 to 130 ppb and 0.00538–190 ppb, respectively. NMDS ordination revealed differences in the presence and concentrations of PPCPs in lake sturgeon serum across sites, however, N,N-diethyl-meta-toluamide (DEET), hydrocortisone, benztropine, and amitriptyline were detected in at least one serum sample at all sites. Additionally, DEET, 10-hydroxy-amitriptyline, and sertraline were detected in ≥25% of gamete samples collected from the St. Lawrence River. Twenty-six PBDE congeners were identified in 25% of serum samples and 24 were identified in 25% of gamete samples. PBDEs in serum were present across all sites and in gametes of St. Lawrence River lake sturgeon, and total PBDE concentrations in serum and gametes ranged from 0.184 to 12.7 ppb and 0.0826–0.44 ppb, respectively. Managers of lake sturgeon populations may need to consider the impacts of CECs if reproductive, developmental, behavioral, growth effects, or mortality are observed in the Great Lakes basin or other areas that are impacted by increased exposures to PPCPs and PBDEs.
... The environmental occurrence of BCs downstream from WWTP outfalls have been shown to adversely affect fish health in several studies (Vajda et al., 2008;Corcoran et al., 2010;Barber et al., 2011;Jorgenson et al., 2018;Meador et al., 2018), and mixtures of BCs may be considerably more toxic or active than the individual components of the mixture (Hayes et al., 2006;Wolfe et al., 2015;Heys et al., 2016;Parrish et al., 2019). In other cases, enhancements in treatment plant operations have been shown to improve conditions for fish Völker et al., 2016;Hicks et al., 2017;Marjan et al., 2017). Suspended sediments and plankton could also be accumulating BCs (Lahti and Oikari, 2011;Bai and Acharya, 2017;Fan et al., 2017) and hence be an additional source of exposure for Asian carp. ...
Article
Two non-native carp species have invaded the Illinois Waterway and are a threat to Great Lakes ecosystems. Poor water quality in the upper Illinois Waterway may be a factor contributing to the stalling of the carp population front near river mile 278. In 2015, the U.S. Geological Survey collected 4 sets of water samples from two sites upstream and 4 sites downstream from river mile 278, and one tributary. Each sample was analyzed for up to 649 unique constituents of which 287 were detected including 96 pesticides, 62 pharmaceuticals, 39 wastewater indicator chemicals, 29 metals, 19 volatile organic compounds (VOCs), 6 disinfection by-products (DBPs), 5 hormones, and 5 carboxylic acids. Potential for bioactivity was estimated by comparing chemical concentrations to aquatic life or human health criteria and to in-vitro bioactivity screening results in the U.S Environmental Protection Agency ToxCast™ database. The resulting hazard quotients and exposure-activity ratios (EARs) are toxicity indexes that can be used to rank potential bioactivity of individual chemicals and chemical mixtures. This analysis indicates that several bioactive chemicals (BCs) including: carbendazim, 2,4-D, metolachlor, terbuthylazine, and acetochlor (pesticides); 1,4-dioxane (VOC); metformin, diphenhydramine, sulfamethoxazole, tramadol, fexofenadine, and the anti-depressants (pharmaceuticals); bisphenol A, 4-nonylphenol, galaxolide, 4-tert-octylphenol (wastewater indicator chemical); lead and boron (metals); and estrone (hormone) all occur in the upper Illinois Waterway at concentrations that produce elevated EARs values and may be adversely affecting carp reproduction and health. The clear differences in water quality upstream and downstream from river mile 278 with higher contaminant concentrations and potential bioactivity upstream could represent a barrier to carp range expansion.
... Urban land use, the number of surface water discharge permits (including wastewater discharges) and the number of known contaminated sites were all positively correlated to estrogenicity in our study. Although we did not have enough sites to statistically compare intersex data to known point sources, similar to other studies [51,52], the presence of these point sources could have contributed to intersex observed across our study area. However, for several of the impoundments (Echo Lake, Canistear Reservoir and Splitrock Reservoir), there are no well-defined point sources that would contribute endocrine active chemicals into the impoundments where fish were sampled during the New Jersey reconnaissance study. ...
Article
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The observation of testicular oocytes in male fishes has been utilized as a biomarker of estrogenic endocrine disruption. A reconnaissance project led in the Northeastern United States (US) during the period of 2008–2010 identified a high prevalence of intersex smallmouth bass on or near US Fish & Wildlife Service National Wildlife Refuges that included the observation of 100% prevalence in smallmouth bass males collected from the Wallkill River, NJ, USA. To better assess the prevalence of intersex smallmouth bass across the state of New Jersey, a tiered reconnaissance approach was initiated during the fall of 2016. Surface water samples were collected from 101 (85 river, 16 lake/reservoir) sites across the state at base-flow conditions for estrogenicity bioassay screening. Detectable estrogenicity was observed at 90% of the sites and 64% were above the US Environmental Protection Agency trigger level of 1 ng/L. Median surface water estrogenicity was 1.8 ng/L and a maximum of 6.9 ng/L E2EqBLYES was observed. Adult smallmouth bass were collected from nine sites, pre-spawn during the spring of 2017. Intersex was identified in fish at all sites, and the composite intersex prevalence was 93.8%. Prevalence across sites ranged from 70.6% to 100%. In addition to intersex, there was detectable plasma vitellogenin in males at all sites. Total estrogenicity in surface water was determined at these fish collection sites, and notable change over time was observed. Correlation analysis indicated significant positive correlations between land use (altered land; urban + agriculture) and surface water estrogenicity. There were no clear associations between land use and organismal metrics of estrogenic endocrine disruption (intersex or vitellogenin). This work establishes a baseline prevalence of intersex in male smallmouth bass in the state of New Jersey at a limited number of locations and identifies a number of waterbodies with estrogenic activity above an effects-based threshold.
... This resulted in improved effluent quality with regard to nutrients, pharmaceuticals, and estrogenicity and, astonishingly, a reduction to less than 10% intersex postupgrade. 147 Perinatal Di-(2-ethylhexyl) Phthalate Exacerbates Anaphylaxis in Male Mouse Offspring, by Emily Mackey This work, which was conducted at the laboratory of Dr Adam Moeser at Michigan State University, stems from the discovery of a sexually dimorphic mast cell phenotype and associated disease pathophysiology. 148 Previously published data have demonstrated that adult female mice exhibited greater serum histamine and more severe mast cell-associated pathophysiology in response to immunoglobulin E (IgE)-mediated anaphylaxis and restraint stress models of mast cell activation, compared with males. ...
Article
During the past 20 years, investigations involving endocrine active substances (EAS) and reproductive toxicity have dominated the landscape of ecotoxicological research. This has occurred in concert with heightened awareness in the scientific community, general public, and governmental entities of the potential consequences of chemical perturbation in humans and wildlife. The exponential growth of experimentation in this field is fueled by our expanding knowledge into the complex nature of endocrine systems and the intricacy of their interactions with xenobiotic agents. Complicating factors include the ever-increasing number of novel receptors and alternate mechanistic pathways that have come to light, effects of chemical mixtures in the environment versus those of single EAS laboratory exposures, the challenge of differentiating endocrine disruption from direct cytotoxicity, and the potential for transgenerational effects. Although initially concerned with EAS effects chiefly in the thyroid glands and reproductive organs, it is now recognized that anthropomorphic substances may also adversely affect the nervous and immune systems via hormonal mechanisms and play substantial roles in metabolic diseases, such as type 2 diabetes and obesity.
... Plants OX, MH, HG, and E were operated to nitrify (Table 2) and showed high removal of TCS (Fig. 3). Removal of trace contaminants has been correlated with degree of nitrification in other studies (Batt et al. 2006;Hicks et al. 2017;Servos et al. 2005;Smyth et al. 2008). Lozano and coworkers reported high removal of TCS during nitrificationdenitrification processes (Lozano et al. 2013). ...
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Triclosan (TCS) is an antimicrobial agent used in many personal care and cleaning products. It has been detected in most environmental compartments and the main entry pathway is wastewater effluents and biosolids. TCS was analyzed in 300 samples of raw influent, final effluent, and biosolids from 13 wastewater treatment plants (WWTPs) across Canada representing five types of typical wastewater treatment systems. TCS was almost always detected in influent (median 1480 ng/L), effluent (median 107 ng/L), and biosolids (median 8000 ng/g dry weight) samples. Removals of TCS from lagoons as well as secondary and advanced treatment facilities were significantly higher than primary treatment facilities (p < 0.001). TCS removal was strongly correlated with organic nitrogen removal. TCS removals at most lagoons and plants that use biological treatment were higher during summer compared with winter. However, no seasonal or temperature effects were observed at the two primary facilities, likely due to the absence of biological activity. Aerobically digested solids contained the lowest levels (median 555 ng/g) while anaerobically digested primary solids contained the highest levels of TCS (median 22,700 ng/g). The results of this large comprehensive study demonstrate that TCS is consistently present in wastewater and biosolids at relatively high concentrations and that removal from wastewater and levels in biosolids are strongly influenced by the wastewater and solids treatment types.
... Although outfall concentrations are sometimes reduced (e.g. acetaminophen, oestrogens) by more advanced treatment processes -and with subsequent benefits downstream (Hicks et al., 2017) -some emerging contaminants (carbazepine, triclosan and diclofenac) are more recalcitrant and require the development of novel interventions (e.g. Bean et al., 2016). ...
Article
In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world's lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth's surface, these ecosystems host at least 9.5% of the Earth's described animal species. Furthermore, using the World Wide Fund for Nature's Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e‐commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem‐level changes through bottom‐up and top‐down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation‐oriented actions (e.g. dam removal, habitat protection policies, managed relocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.
... Where technological improvements of sewage treatment have been implemented, there have been reductions in intersex (feminised) fish caused by steroid oestrogens and their mimics, as well as improvements in river biodiversity. 40,41 These improvements, however, are costly. Owen and Jobling (2012) 42 estimated that upgrading all the WWTPs in England and Wales to comply with EU regulation to bring synthetic oestrogens below an average of 0.035 pg/L ethinylestradiol per annum would cost an estimated £26 billion. ...
Article
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The influence of pharmaceuticals on the environment is an increasing concern among environmental toxicologists. It is known that their growing use is leading to detectable levels in wastewater, conceivably causing harm to aquatic ecosystems. Psychotropic medication is one such group of substances, particularly affecting high-income countries. While these drugs have a clear place in therapy, there is debate around the risk/benefit ratio in patients with mild mental health problems. Therefore, it is necessary to evaluate the wider implications as risks could extend beyond the individual to non-target organisms, particularly those in rivers and estuaries. Declaration of interest None.
... To close this gap, several case studies were conducted during the last years which proved biological effect monitoring based on biotests and biomarkers to be a useful tool to assess the effluentrelated risk for aquatic organisms [11,12]. Moreover, comparison of data obtained prior and subsequent to the installation of a new wastewater treatment technology [13][14][15][16][17][18] or of samples taken at different steps within the treatment process [19,20] was shown to be a valuable strategy to evaluate the efficiency of this new technology. Especially in situ exposure (active monitoring) of caged fish has often been applied in this context [21,22]. ...
Article
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Background In situ exposure of rainbow trout up- and downstream of differently equipped wastewater treatment plants (WWTPs) and subsequent analyses of micronuclei frequencies and hepatic EROD activities were used to evaluate the impact of the effluents on fish health. Two of the facilities (WWTPs A and B) were conventional treatment plants. WWTP C has been equipped with a powdered activated carbon stage. Here, analyses were conducted prior and subsequent to this upgrade. Results Differences did not only occur when comparing conventional (WWTPs A, B and C prior to the upgrade) and advanced treatment (WWTP C after the upgrade), but also between the conventionally equipped WWTPs. There was no indication for genotoxic effects or pollution-related EROD induction in fish exposed at WWTP A. In contrast, trout exposed at WWTP B expressed strong reactions. However, here, adverse reactions were also observed in fish kept upstream. Similar observations were made for EROD activities in fish exposed at WWTP C prior to the upgrade, whereas genotoxic effects could only be seen in trout kept downstream of this effluent. Upgrading of WWTP C resulted in a significant reduction of both genotoxic effects and EROD levels. Conclusions The results show financial investments in advanced wastewater treatment to be beneficial for aquatic ecosystems, especially when conventional technologies do not sufficiently remove pollutants. Yet, negative impacts of effluents on aquatic organisms can, under certain conditions, also be avoided by conventional treatment. Therefore, we recommend deciding on the necessity and the type of WWTP upgrading on a case-by-case basis.
... Conventional sewage treatment has been reported to reduce EDCs significantly from high levels, for example 50 ng l −1 to below 0.75 ng l −1 (Leusch et al. 2005) and with EDCs removal efficiencies ranging from 70% to 100% (Kirk et al. 2002). Moreover, improved wastewater treatment in some cities has resulted in improved effluent quality and reduced effects of EDCs in the environment (Hicks et al. 2017). However, Bulawayo, and many other cities in developing countries, are characterised by aging and dysfunctional STP infrastructure. ...
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Peri-urban water bodies are at risk from excessive pollution as they are direct sinks for urban effluents. The occurrence of oestrogenic and androgenic endocrine disrupting chemicals (EDCs) in effluents and water bodies around the city of Bulawayo, Zimbabwe, and their effects on wild fish was investigated in 2013. Effluent and water were sampled from sewage treatment plants, an urban stream, and effluent-polluted dams, and were compared with a ‘pristine’ dam upstream of Bulawayo. Organic pollutants were extracted by solid-phase extraction and tested for EDCs using a yeast oestrogen/androgen screen. Oestrogenic and androgenic potencies were expressed as 17β-oestradiol equivalent (EEq) or dihydrotestosterone equivalent (TEq). Tilapia and catfish from the dams were analysed for gonado-somatic indices and testis histopathology. Effluents from STPs, which directly flow into Umguza Dam, had EEq of 33 ng l⁻¹ and 55 ng l⁻¹, respectively. Umguza Dam, Khami Dam and Matsheumhlope Stream had EEqs of 237 ng l–1, 9 ng l⁻¹ and 2 ng l⁻¹, respectively. Androgenic activity was detected in only one STP (TEq = 93 ng l⁻¹). Tilapia sampled from effluent-polluted dams had high incidences of testis-ova, but catfish had no signs of reproductive dysfunction. These findings underscore the need for greater attention to EDCs in developing countries where there is scant literature regarding their occurrence and impacts.
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Endocrine disruption of wild fish, primarily resulting in the feminization of males, has been reported in English river sites for several decades. Estrogenic activity emanating from wastewater treatment works (WwTW) has been conclusively demonstrated to be the main driver of these feminized phenotypes. Here, we revisit 10 English river sites previously surveyed in the late 1990s and early 2000s to assess how the frequency and severity of feminization now compare with the historical surveys. In the contemporary assessment, 60% of the sites revisited still showed endocrine disruption at the tissue organization level (oocytes present in otherwise male gonads; intersex) and 90% of sites had average male plasma vitellogenin concentrations (female-specific yolk protein; a sensitive biomarker of estrogen exposure) above natural baseline levels. In contrast to the historic surveys, none of the males sampled in the contemporary survey had ovarian cavities. At one of the larger WwTW, improvements to treatment technology may have driven a significant reduction in intersex induction, whereas at several of the smaller WwTW sites, the frequencies of feminization did not differ from those observed in the late 1990s. In conclusion, we show that although the severity of feminization is now reduced at many of the revisited sites, endocrine-disrupting chemicals are still impacting wild fish living downstream of WwTW in England.
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To evaluate relationships between different anthropogenic impacts, contaminant occurrence, and fish health, we conducted in situ fish exposures across the Shenandoah River watershed at five sites with different land use. Exposure water was analyzed for over 500 chemical constituents, and organismal, metabolomic, and transcriptomic endpoints were measured in fathead minnows. Adverse reproductive outcomes were observed in fish exposed in the upper watershed at both wastewater treatment plant (WWTP) effluent- and agriculture-impacted sites, including decreased gonadosomatic index and altered secondary sex characteristics. This was accompanied with increased mortality at the site most impacted by agricultural activities. Molecular biomarkers of estrogen exposure were unchanged and consistent with low or non-detectable concentrations of common estrogens, indicating that alternative mechanisms were involved in organismal adverse outcomes. Hepatic metabolomic and transcriptomic profiles were altered in a site-specific manner, consistent with variation in land-use and contaminant profiles. Integrated biomarker response data were useful for evaluating mechanistic linkages between contaminants and adverse outcomes, suggesting that reproductive endocrine disruption, altered lipid processes, and immunosuppression may have been involved in these organismal impacts. This study demonstrated linkages between human-impact, contaminant occurrence, and exposure effects in the Shenandoah River watershed and showed increased risk of adverse outcomes in fathead minnows exposed to complex mixtures at sites impacted by municipal wastewater discharges and agricultural practices.
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Fish live in continuous contact with various stressors and antigenic material present within their environments. The impact of stressors associated with wastewater-exposed environments on fish has become of particular interest in toxicology studies. The objectives of this study were to examine potential effects of wastewater treatment plant (WWTP) effluent-associated stressors on innate cytokine expression within the gills of darter species (Etheostoma spp.), using both field and laboratory approaches. Male and female darters (rainbow, greenside, fantail, and johnny darters) were collected upstream and downstream of the Waterloo WWTP in the Grand River, Ontario. Gill samples were collected from fish in the field and from a second subset of fish brought back to the laboratory. Laboratory fish were acutely exposed (96-h) to an environmentally relevant concentration of venlafaxine (1.0 μg/L), a commonly prescribed antidepressant. To assess the impacts of these stressors on the innate immunity of darters, the expression of key innate cytokines was examined. Minor significant effects on innate cytokine expression were observed between upstream and downstream fish. Moderate effects on cytokine expression were observed in venlafaxine-exposed fish compared to their control counterparts however, changes were not indicative of a biologically significant immune response occurring due to the exposure. Although the results of this study did not display extensive impacts of effluent and pharmaceutical exposure on innate cytokine expression within the gills, they provide a novel avenue of study, illustrating the importance of examining potential impacts that effluent-associated stressors can have on fundamental immune responses of native fish species.
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Best management practices (BMPs) have been predominantly used throughout the Chesapeake Bay watershed (CBW) to reduce nutrients and sediments entering streams, rivers, and the bay. These practices have been successful in reducing loads entering the estuary and have shown the potential to reduce other contaminants (pesticides, hormonally active compounds, pathogens) in localized studies and modeled load estimates. However, further understanding of relationships between BMPs and non-nutrient contaminant reductions at regional scales using sampled data would be beneficial. Total estrogenic activity was measured in surface water samples collected over a decade (2008–2018) in 211 undeveloped NHDPlus V2.1 watersheds within the CBW. Bayesian hierarchical modeling between total estrogenic activity and landscape predictors including landcover, runoff, BMP intensity, and a BMP*agriculture intensity interaction term indicates a 96% posterior probability that BMP intensity on agricultural land is reducing total estrogenic activity. Additionally, watersheds with high agriculture and low BMPs had a 49% posterior probability of exceeding an effects-based threshold in aquatic organisms of 1 ng/L but only a 1% posterior probability of exceeding this threshold in high-agriculture, high-BMP watersheds.
Chapter
In our current ecological moment, our planet is becoming increasingly toxic as a result of human consumption. Within this toxic era, media outlets, scientists, and environmentalists rely on intersex human and non-human animal bodies to make obvious the negative effects of human made chemicals on our Planet. Malin Ah-King and Eva Hayward argue that instead of engaging in this “transsex panic” we must understand sex and gender as part of an ongoing process of sexing. Ah-King and Hayward’s understanding of sex as an ever-evolving process does not, however, contend with intersex human bodies that are bearing the physical burden of “transsex panic” through immediate medical intervention at birth and beyond. In response, this chapter offers a reading of Aaron Apps’ poetry collection entitled Intersex: A Memoir, as a text that imagines the speaker’s intersex body as already toxified and magnificent so as to represent intersex thriving in our toxic age.
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The application of some hormones in fish production in swamps enhances fish production. However, in this regard, the critical issue is chemical contamination in water, which affects aquatic organisms. Steroid hormones (e.g., androgens and estrogens) can change the sexual characteristics of aquatic organisms, especially fish. These compounds are used in oral contraceptives and have an effect on fish at different developmental stages, such as the development of an embryo. The residual effects of steroid hormones can adversely affect the environment, biological activities, and human health. Furthermore, these hormones negatively affect the endocrine system in marine organisms. Therefore, the identification and measure of these compounds by sensitive and selective analytical methods is not only essential, but can also prevent their adverse effects. Estrone (E1), 17β-estradiol (17β-E2), and 17α-ethynylestradiol (EE2) are current steroid hormones, which create feminized properties in male fish. The concentration of E1 in aquatic surroundings is more than the concentration of estradiol (E2) and EE2; however, E1 has a low connection and activation power to the estrogen receptor (ER). Hence, the 17β-hydroxysteroid dehydrogenases (17β-HSDs) enzyme converts E1 to E2, especially in an environment with a high E1 concentration, such as wastewater treatment. Researchers showed that E1 and its conversion have dangerous impacts on the generation and breeding of different fish species in polluted aquatic environments. In this regard, the goal of this systematic review is to evaluate the role of steroid hormones in aquatic organisms, especially fish, as well as to evaluate the negative consequences of these compounds on humans and the surrounding.
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Effluents from municipal wastewater treatment plants (MWTPs) are complex mixtures of chemicals including endocrine-disrupting compounds (EDCs) and 17α-ethynylestradiol (EE2). The objective of this study was to evaluate selected responses of two fish species, in two different years, exposed in situ to MWTP effluent. Biological markers of exposure (plasma vitellogenin (VTG) and antioxidant enzymes) were measured in two species of male fish, rainbow trout (Oncorhynchus mykiss) and fathead minnow (Pimephales promelas), caged at sites associated with wastewater outfall. The estrogenicity of the final effluent in 2010 was determined to be 17.0 + 0.4 ng/L estrogen equivalents (EEQ) and reduced to 7.5 + 2.9 ng/L EEQ after infrastructure upgrades. Pharmaceuticals and personal care products in the effluent and surface water in both years confirmed the exposures at each downstream site. Despite the presence of estrogenic compounds in the MWTP effluent, no effluent-caged male fish demonstrated plasma VTG induction. Minnows and trout that received an intraperitoneal injection of 5 mg/g EE2 showed VTG induction at both field sites. In 2012, the liver somatic index (LSI) of both species increased with exposure, as did changes in antioxidant enzymes, and reactive oxygen species (ROS) activity. Multiple biological mechanisms are modified by effluent exposure, and multiple endpoints are needed to assess risk. HIGHLIGHTS Effluent exposure resulted in induction of antioxidant enzymes and ROS activity in caged fish.; Despite measurable estrogen equivalents in the effluent, downstream caged male fathead minnow did not demonstrate VTG induction.; EE2 injected, control male fish exposed to wastewater or upstream reference conditions responded with elevated VTG concentrations.; Several factors may have reduced the VTG response in caged fish.;
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During recent decades, survey studies have documented the widespread presence of oocytes in the testes of male Smallmouth Bass Micropterus dolomieu collected from surface waters throughout the United States. There are few published reports of testicular oocytes (TO) in Smallmouth Bass before the 1990s, so it is difficult to know how long this has been occurring. Consequently, this study was conducted to evaluate the prevalence and severity of TO occurrence in whole fish specimens from two archival collections-the Smithsonian Institution's National Museum of Natural History in Suitland, Maryland, and Cornell University's Museum of Vertebrates in Ithaca, New York. Gonads were excised from 167 preserved male Smallmouth Bass that were originally collected between 1875 and 2004, and routine histologic sections were prepared and examined. The severity of TO was determined using a semiquantitative scoring system. Overall, 52.1% of male Smallmouth Bass were found to have TO. Affected fish had been collected in 11 of the 18 represented states, and TO were found in specimens harvested during decades as early as the 1880s and 1900s. Unfortunately, the small number of samples acquired at the earliest time periods precluded analyses of prevalence and severity trends over time. The results of this study demonstrated that the phenomenon of TO in male Smallmouth Bass is at least a century old and confirmed the widespread nature of this finding throughout the species' historic range. Further research efforts should focus on determining the baseline prevalence of TO in laboratory-reared male Smallmouth Bass that have not been exposed to endocrine active substances or the effects of experimental estrogen exposure on such fish.
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While wastewater treatment standards have been progressively increasing, emerging contaminants such as pharmaceuticals can nonetheless pass through treatment and end up in our watersheds. Pharmaceuticals in the parts-per-billion range can impact fish behavior, survival, and recruitment in the wild. However, the ecological risk posed by whole municipal wastewater effluents (MWWE), a complex mixture, is not clear. This knowledge gap is particularly evident for early lifestages (ELS) of fish, and because effluent discharge events are typically short, the effects of short-term MWWE exposures to ELS fish are particularly important from an environmental perspective. Here we tested the effects of rapid 30-min exposures, and short-term 24- and 72-h exposures to MWWE on development, behaviors, and stress response in zebrafish (Danio rerio) embryos, larvae, and juveniles. We obtained 24-h composite samples of tertiary-treated MWWE that contained a mixture of chemicals with affinities for serotonergic, adrenergic, dopaminergic, and ion-channel receptors. Embryos exposed to 5%, 10%, and 50% MWWE experienced developmental delays in somitogenesis and hatching rate, although there was no effect on survival. Embryonic photomotor responses were affected following 30-min and 24-h exposures to 10% and 50% MWWE, and larval visual motor responses were reduced from 24-h exposure to 10% MWWE. Exposure to 10% MWWE dulled the juvenile cortisol and lactate response following an acute air-exposure. Compromised behavioral and stress performances demonstrate the capacity of MWWE to impact phenotypes critical to the survival of fish in the environment. Taken together, we found that zebrafish were sensitive to toxic effects of MWWE at multiple life-stages.
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Recent evidence has revealed that cities with pharmaceutical manufacturers have elevated concentrations of Active Pharmaceutical Ingredients (APIs) in their receiving water bodies. The purpose of this study was to gather information on direct sewer discharges of APIs during their manufacturing and processing from five pharmaceutical manufacturing facilities in Ontario, Canada. Drug classes and maximum reported concentrations (ng/L) for which APIs were directly discharged included: antidepressants (paroxetine - 3380 and sertraline - 5100); mood stabilizer (carbamazepine - 575,000); antibiotics (penicillin - 14,300); analgesics (acetaminophen - 461,000; codeine - 49,200; ibuprofen - 344,000; naproxen - 253,000 and oxycodone 21,000); cardiovascular drugs (atorvastatin - 893 and metoprolol - 7,333,600) and those drugs used for blood pressure control (amlodipine - 22,900; diltiazem - 1,160,000; furosemide - 1,200,000 and verapamil - 7340). Based on flow and water usage data from the individual facilities, the maximum concentrations for acetaminophen, ibuprofen, carbamazepine, diltiazem and metoprolol correlate to approximately 200, 220, 390, 420 and 14,200 g respectively, of lost product being directly discharged to the sewers daily during active manufacturing. This survey demonstrates that direct point source discharges from pharmaceutical manufacturers represent a key source of pharmaceutical pollution to receiving sewersheds. Onsite recovery of product or treatment at pharmaceutical manufacturing or processing facilities to reduce the sewage loadings to receiving treatment plants, product loss and potential environmental loadings is strongly recommended.
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Endocrine active compounds (EACs) are pollutants that have been recognized as an emerging and widespread threat to aquatic ecosystems globally. Intersex, the presence of female germ cells within a predominantly male gonad, is considered a biomarker of endocrine disruption caused by EACs. We measured a suite of EACs and assessed their associated impacts on fish intersex occurrence and severity in a large, regulated river system in North Carolina and South Carolina, USA. Our specific objective was to determine the relationship of contaminants in water, sediment, and fish tissue with the occurrence and severity of the intersex condition in wild, adult black bass (Micropterus), sunfish (Lepomis), and catfish (Ictaluridae) species at 11 sites located on the Yadkin-Pee Dee River. Polycyclic aromatic hydrocarbons (PAHs), ethinylestradiol (EE2), and heavy metals were the most prevalent contaminants that exceeded effect levels for the protection of aquatic organisms. Fish intersex condition was most frequently observed and most severe in black basses and was less frequently detected and less severe in sunfishes and catfishes. The occurrence of the intersex condition in fish showed site-related effects, rather than increasing longitudinal trends from upstream to downstream. Mean black bass and catfish tissue contaminant concentrations were higher than that of sunfish, likely because of the latter's lower trophic position in the food web. Principal component analysis identified waterborne PAHs as the most correlated environmental contaminant with intersex occurrence and severity in black bass and sunfish. As indicated by the intersex condition, EACs have adverse but often variable effects on the health of wild sport fishes in this river, likely due to fluctuations in EAC inputs and the dynamic nature of the riverine system. These findings enhance the understanding of the relationship between contaminants and fish health and provide information to guide ecologically comprehensive conservation and management decisions.
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Decades of studies on endocrine disruption have suggested the need to manage the release of key estrogens from municipal wastewater treatment plants (WWTP). However, the proposed thresholds are below the detection limits of most routine chemical analysis, thereby restricting the ability of watershed managers to assess the environmental exposure appropriately. In this study, we demonstrated the utility of a mechanistic model to address the data gaps on estrogen exposure. Concentrations of the prominent estrogenic contaminants in wastewaters (estrone, estradiol, and ethinylestradiol) were simulated in the Grand River in southern Ontario (Canada) for nine years, including a period when major WWTP upgrades occurred. The predicted concentrations expressed as total estrogenicity (E2 equivalent concentrations) were contrasted to a key estrogenic response (i.e., intersex) in rainbow darter (Etheostoma caeruleum), a wild sentinel fish species. A predicted total estrogenicity in the river of ≥10 ng/L E2 equivalents was associated with high intersex incidence and severity, whereas concentrations <0.1 ng/L E2 equivalents were associated with minimal intersex expression. Exposure to a predicted river concentration of 0.4 ng/L E2 equivalents, the environmental quality standard (EQS) proposed by the European Union for estradiol, was associated with 34% (95% CI:30-38) intersex incidence and a very low severity score of 0.6 (95% CI:0.5-0.7). This exposure is not predicted to cause adverse effects in rainbow darter. The analyses completed in this study were only based on the predicted presence of three major estrogens (E1, E2, EE2), so caution must be exercised when interpreting the results. Nevertheless, this study illustrates the use of models for exposure assessment, especially when measured data are not available.
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Municipal wastewater effluent (MWWE) and its constituents, such as chemicals of emerging concern, pose a potential threat to the sustainability of fish populations by disrupting key endocrine functions in aquatic organisms. While studies have demonstrated changes in biological markers of exposure of aquatic organisms to groups of chemicals of emerging concern, the variability of these markers over time has not been sufficiently described in wild fish species. The aim of this study was to assess the spatial and temporal variability of biological markers in response to MWWE exposure and to test the consistency of these responses between seasons and among years. Rainbow darter ( Etheostoma caeruleum ) were collected in spring and fall seasons over a 5-year period in the Grand River, Ontario, Canada. In addition to surface water chemistry (nutrients and selected pharmaceuticals), measures were taken across levels of biological organization in rainbow darter. The measurements of hormone production, gonad development, and intersex severity were temporally consistent and suggested impaired reproduction in male fish collected downstream of MWWE outfalls. In contrast, ovarian development and hormone production in females appeared to be influenced more by urbanization than MWWE. Measures of gene expression and somatic indices were highly variable between sites and years, respectively, and were inconclusive in terms of the impacts of MWWE overall. Robust biomonitoring programs must consider these factors in both the design and interpretation of results, especially when spatial and temporal sampling of biological endpoints is limited. Assessing the effects of contaminants and other stressors on fish in watersheds would be greatly enhanced by an approach that considers natural variability in the endpoints being measured.
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The occurrence of intersex fish, where male reproductive tissues show evidence of feminization, have been found in freshwater systems around the world, indicating the potential for significant endocrine disruption across species in the ecosystem. Estrogens from birth control medications in wastewater treatment plant effluent have been cited as the likely cause, but research has shown that endocrine disruption is not solely predictable based on hormone receptor interactions. Many other non-hormone pharmaceuticals are found in effluent at concentrations orders of magnitude higher than estrogens, yet there is little data indicating the impacts of these other medications. The widely prescribed anti-diabetic metformin is among the most abundant of pharmaceuticals found in effluent and is structurally dissimilar from hormones. However, we show here that exposing fathead minnows (Pimephales promelas) to a concentration of metformin found in wastewater effluent causes the development of intersex gonads in males, reduced size of treated male fish, and reduction in fecundity for treated pairs. Our results demonstrate that metformin acts as an endocrine disruptor at environmentally relevant concentrations. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Endocrine-disrupting chemicals (EDCs) in municipal effluents directly affect the sexual development and reproductive success of fishes, but indirect effects on invertebrate prey or fish predators through reduced predation or prey availability, respectively, are unknown. At the Experimental Lakes Area in northwestern Ontario, Canada, a long-term, whole-lake experiment was conducted using a before-after-control-impact design to determine both direct and indirect effects of the synthetic oestrogen used in the birth control pill, 17 alpha-ethynyloestradiol (EE2). Algal, microbial, zooplankton and benthic invertebrate communities showed no declines in abundance during three summers of EE2 additions (5-6 ng l(-1)), indicating no direct toxic effects. Recruitment of fathead minnow (Pimephales promelas) failed, leading to a near-extirpation of this species both 2 years during (young-of-year, YOY) and 2 years following (adults and YOY) EE2 additions. Body condition of male lake trout (Salvelinus namaycush) and male and female white sucker (Catostomus commersonii) declined before changes in prey abundance, suggesting direct effects of EE2 on this endpoint. Evidence of indirect effects of EE2 was also observed. Increases in zooplankton, Chaoborus, and emerging insects were observed after 2 or 3 years of EE2 additions, strongly suggesting indirect effects mediated through the reduced abundance of several small-bodied fishes. Biomass of top predator lake trout declined by 23-42% during and after EE2 additions, most probably an indirect effect from the loss of its prey species, the fathead minnow and slimy sculpin (Cottus cognatus). Our results demonstrate that small-scale studies focusing solely on direct effects are likely to underestimate the true environmental impacts of oestrogens in municipal wastewaters and provide further evidence of the value of whole-ecosystem experiments for understanding indirect effects of EDCs and other aquatic stressors.
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1. Increased need for water and projected declines in precipitation due to climate change could leave waterways increasingly dominated by wastewater effluent. Understanding how components of wastewater influence fish populations is necessary for effective conservation and management. Despite research demonstrating effects of oestrogens, such as 17a-ethynylestradiol (EE2), on fish physiology and population failure, the generality of population responses is uncertain and the underlying mechanisms affecting population declines are unknown. EE2 is the steroid oestrogen in human contraceptive pills and has been measured up to 11 ng L ^-1 in the environment. 2. We identify disrupted population dynamics due to direct and transgenerational effects on survival and fecundity. We conducted a year-long study on three generations of fathead minnows Pimephales promelas Rafinesque in aquatic mesocosms and laboratory aquaria. We added environmentally relevant concentrations of EE2 daily using a static renewal, which approximates a pulsed exposure that fish experience in natural systems. 3. EE2 (3*2 ng L ^-1) reduced F0 male survival to 17% (48% lower than controls) and juvenile production by 40% compared to controls. F1 fish continuously exposed to EE2 failed to reproduce, and reproduction of the F1 transferred to clean water was 70–99% less than controls. 4. F2 larval survival, exposed only as germ cells in their parents, was reduced by 51–97% compared to controls. The indirect effect on F2 survival suggests the possibility of transgenerational effects of EE2. 5. Synthesis and applications. Our results suggest that fish populations exposed to environmentally relevant 17a-ethynylestradiol (EE2) concentrations may not recover from exposure. Management of short-lived highly fecund fishes should be prioritized to protect fish from the embryo through gonadal differentiation. Reducing effluent will not be possible in many situations; hence, conservation of breeding and rearing habitat in unpolluted tributaries or reaches is needed. Additionally, resource managers could enhance habitat connectivity in rivers to facilitate immigration. Finally, investment in advanced wastewater processing technology should improve removal of bioactive chemicals such as EE2. Our results provide a baseline for regulatory agencies to consider when assessing the ecological effects of environmental oestrogens, and our approach to evaluating population-level effects could be widely applied to other contaminants.
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The variability and extent of the intersex condition (oocytes in testes or testis-ova) in fish along an urban gradient, that included major wastewater treatment plant outfalls, was documented in the Grand River, Ontario, Canada. A rapid enumeration of testis-ova method (RETO) was developed and applied that increased the capacity to quantify both intersex prevalence and severity. Male Rainbow Darters (Etheostoma caeruleum) sampled downstream of the first major wastewater outfall (Waterloo) had a significant increase, relative to four upstream reference sites, in the mean proportion of fish with at least one testis-oocyte (t.o.) per lobe of testes (9-20% proportion with ≤ 1 t.o./lobe vs. 32-53% and >1.4 t.o./lobe). A much higher mean incidence of intersex proportion and degree was observed immediately downstream of the second wastewater outfall (Kitchener; 73-100% and 8-70 t.o./lobe) but only 6.3 km downstream of the Kitchener outfall the occurrence of intersex drops to those of the reference sites. In contrast, downstream of a tertiary treated wastewater outfall on a small tributary intersex was similar to reference sites. Estrogenicity, measured using a Yeast Estrogen Screen (YES), followed a similar pattern increasing from 0.81 ± 0.02 ng/L EEq (Guelph), to 4.32 ± 0.07 ng/L (Waterloo), and 16.99 ± 0.40 ng/L (Kitchener) respectively. Female Rainbow Darter downstream of the Kitchener outfall showed significant decreases in gonadosomatic index (GSI) and liver somatic index (LSI), and increases in condition factor (k) relative to corresponding reference sites. The prevalence of intersex and alterations in somatic indices suggest that exposure to municipal wastewater effluent discharges can impact endocrine function, energy use, and energy storage in wild fish. Environ Toxicol Chem © 2013 SETAC.
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A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected over a 2-year period from three tributaries of the Potomac River: the Shenandoah River, the South Branch Potomac and Conococheague Creek, and an out-of-basin reference site on the Gauley River. The prevalence of TO varied seasonally with the lowest prevalence observed in July, post-spawn. Reproductive maturity and/or lack of spawning the previous spring, as well as land-use practices such as application of manure and pesticides, may influence the seasonal observations. Annual, seasonal, and site differences were also observed in the percentage of males with measurable concentrations of plasma vitellogenin, mean concentration of plasma vitellogenin in females, and plasma concentrations of 17β-estradiol and testosterone in both sexes. Bass collected in the South Branch Potomac (moderate to high prevalence of TO) had less sperm per testes mass with a lower percentage of those sperm being motile when compared to those from the Gauley River (low prevalence of TO). An inverse relationship was noted between TO severity and sperm motility. An association between TO severity and wastewater treatment plant flow, percent of agriculture, total number of animal feeding operations, the number of poultry houses, and animal density within the catchment was observed.
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The Grand River watershed in Ontario, Canada, receives and assimilates the outflow of 29 Municipal Wastewater Effluent (MWWE) discharges which is a mixture of domestic and industrial wastes. The purpose of this study was to investigate the cumulative impact of multiple sewage discharges on populations of wild fish. In field studies, responses of fish populations and individual fish responses in terms of growth (condition factor), reproduction (in vitro sex steroid production, gonadosomatic indices, histology [cellular development and intersex]) were assessed upstream and downstream of two municipal discharges. Fish [Greenside Darters Etheostoma blennioides and Rainbow Darters E. caeruleum] collected downstream of two municipal wastewater plants had the potential to have greater growth (longer and heavier) when compared to reference fish collections regardless of sex. Fish were not assimilating additional anthropogenic resources into energy storage (increased condition, liver somatic index). Impacts on ovarian development appeared to be minor with no differences in growth, steroid production or cellular development. Sewage exposed male fish were experiencing impairment in the capacity to produce testosterone and 11-ketotestosterone in vitro, and in cellular development (GSI, intersex). Male darters of both species collected in the upstream agricultural region demonstrated no evidence of intersex whereas our urban reference sites had incidence of intersex of up to 20%. Rates of intersex were elevated downstream of both sewage discharges studied (33% and>60%, respectively). Lower rates of intersex at the intermediate sites, and then increases downstream of second sewage discharge suggests that fish populations have to potential to recover prior to exposure to the second sewage effluent. Pre-spawning darters demonstrated dramatically higher incidence of intersex in the spring at both urban reference sites (33% and 50%, respectively), and increased more so downstream of the near-field and far-field exposure sites (60% and 100%, respectively). These findings suggest that the compounds released in STP effluents have a tendency to act on the male reproductive system. These effects may become more pronounced as projected human population growth will require the aquatic environment to assimilate an increasing amount of sewage waste.
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The feminization of nature by endocrine-disrupting chemicals (EDCs) is a key environmental issue affecting both terrestrial and aquatic wildlife. A crucial and as yet unanswered question is whether EDCs have adverse impacts on the sustainability of wildlife populations. There is widespread concern that intersex fish are reproductively compromised, with potential population-level consequences. However, to date, only in vitro sperm quality data are available in support of this hypothesis. The aim of this study was to examine whether wild endocrine-disrupted fish can compete successfully in a realistic breeding scenario. In two competitive breeding experiments using wild roach (Rutilus rutilus), we used DNA microsatellites to assign parentage and thus determine reproductive success of the adults. In both studies, the majority of intersex fish were able to breed, albeit with varying degrees of success. In the first study, where most intersex fish were only mildly feminized, body length was the only factor correlated with reproductive success. In the second study, which included a higher number of more severely intersex fish, reproductive performance was negatively correlated with severity of intersex. The intersex condition reduced reproductive performance by up to 76% for the most feminized individuals in this study, demonstrating a significant adverse effect of intersex on reproductive performance. Feminization of male fish is likely to be an important determinant of reproductive performance in rivers where there is a high prevalence of moderately to severely feminized males.
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The yeast estrogen screen was applied to sewage treatment process waters to identify the presence of estrogenic activity and to investigate the fate and behavior of estrogenic substances through treatment. Hydrophobic fractions in the water phase were extracted and concentrated using C18 cartridges for the effective extraction of 17β-estradiol (E2) and other estrogen mimics. Clear dose-dependent elevation in the synthesis of β-galactosidase in the yeast screen was observed with all the samples tested, demonstrating that these samples were estrogenic. However, estrogenic activity tended to reduce during the treatment, especially in the biological process. Quantification results of the yeast estrogen screen in terms of E2 equivalent were compared with actual E2 concentrations measured by an ELISA. E2 occupied 34% of the whole estrogenicity in the raw sewage, while almost 100% in the final effluent. The analyses of the sewage treatment process waters revealed that human estrogens are major causative substances in terms of estrogenic activity in sewage and its treated effluent. Although findings of possible correlation of environmental estrogens with the real impact on human health and the ecosystem are still the focus of scientific debate and investigation, proper management should be established in the sewage treatment process which receives various environmental contaminants.
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The widespread occurrence of feminized male fish downstream of some wastewater treatment works has led to substantial interest from ecologists and public health professionals. This concern stems from the view that the effects observed have a parallel in humans, and that both phenomena are caused by exposure to mixtures of contaminants that interfere with reproductive development. The evidence for a "wildlife-human connection" is, however, weak: Testicular dysgenesis syndrome, seen in human males, is most easily reproduced in rodent models by exposure to mixtures of antiandrogenic chemicals. In contrast, the accepted explanation for feminization of wild male fish is that it results mainly from exposure to steroidal estrogens originating primarily from human excretion. We sought to further explore the hypothesis that endocrine disruption in fish is multicausal, resulting from exposure to mixtures of chemicals with both estrogenic and antiandrogenic properties. We used hierarchical generalized linear and generalized additive statistical modeling to explore the associations between modeled concentrations and activities of estrogenic and antiandrogenic chemicals in 30 U.K. rivers and feminized responses seen in wild fish living in these rivers. In addition to the estrogenic substances, antiandrogenic activity was prevalent in almost all treated sewage effluents tested. Further, the results of the modeling demonstrated that feminizing effects in wild fish could be best modeled as a function of their predicted exposure to both antiandrogens and estrogens or to antiandrogens alone. The results provide a strong argument for a multicausal etiology of widespread feminization of wild fish in U.K. rivers involving contributions from both steroidal estrogens and xenoestrogens and from other (as yet unknown) contaminants with antiandrogenic properties. These results may add further credence to the hypothesis that endocrine-disrupting effects seen in wild fish and in humans are caused by similar combinations of endocrine-disrupting chemical cocktails.
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Endocrine-disrupting chemicals, known to be present in the environment, have great potential for interfering with reproductive health in wildlife and humans. There is, however, little direct evidence that endocrine disruption has adversely affected fertility in any organism. In freshwater and estuarine fish species, for example, although a widespread incidence of intersex has been reported, it is not yet known if intersexuality influences reproductive success. The purpose of this study was, therefore, to determine gamete quality in wild intersex roach (Rutilus rutilus) by assessing sperm characteristics, fertilization success, and ability to produce viable offspring. The results clearly demonstrate that gamete production is reduced in intersex roach. A significantly lower proportion of moderately or severely feminized fish (17.4% and 33.3%, respectively) were able to release milt compared with normal male fish from contaminated rivers (in which 97.6% of the males were able to release milt), reference male fish (97.7%), or less severely feminized intersex fish (experiment 1: 85.8%, experiment 2: 97%). Intersex fish that did produce milt produced up to 50% less (in terms of volume per gram of testis weight) than did histologically normal male fish. Moreover, sperm motility (percentage of motile sperm and curvilinear velocity) and the ability of sperm to successfully fertilize eggs and produce viable offspring were all reduced in intersex fish compared with normal male fish. Male gamete quality (assessed using sperm motility, sperm density, and fertilization success) was negatively correlated with the degree of feminization in intersex fish (r = -0.603; P < 0.001) and was markedly reduced in severely feminized intersex fish by as much as 50% in terms of motility and 75% in terms of fertilization success when compared with either less severely feminized intersex fish or unaffected male fish. This is the first evidence documenting a relationship between the morphological effects (e.g., intersex) of endocrine disruption and the reproductive capabilities of any wild vertebrate. The results suggest that mixtures of endocrine-disrupting substances discharged into the aquatic environment could pose a threat to male reproductive health.
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Surveys of U.K. rivers have shown a high incidence of sexual disruption in populations of wild roach (Rutilus rutilus) living downstream from wastewater treatment works (WwTW), and the degree of intersex (gonads containing both male and female structural characteristics) has been correlated with the concentration of effluent in those rivers. In this study, we investigated feminized responses to two estrogenic WwTWs in roach exposed for periods during life stages of germ cell division (early life and the postspawning period). Roach were exposed as embryos from fertilization up to 300 days posthatch (dph; to include the period of gonadal sex differentiation) or as postspawning adult males, and including fish that had received previous estrogen exposure, for either 60 or 120 days when the annual event of germ cell proliferation occurs. Both effluents induced vitellogenin synthesis in both life stages studied, and the magnitude of the vitellogenic responses paralleled the effluent content of steroid estrogens. Feminization of the reproductive ducts occurred in male fish in a concentration-dependent manner when the exposure occurred during early life, but we found no effects on the reproductive ducts in adult males. Depuration studies (maintenance of fish in clean water after exposure to WwTW effluent) confirmed that the feminization of the reproductive duct was permanent. We found no evidence of ovotestis development in fish that had no previous estrogen exposure for any of the treatments. In wild adult roach that had previously received exposure to estrogen and were intersex, the degree of intersex increased during the study period, but this was not related to the immediate effluent exposure, suggesting a previously determined programming of ovotestis formation.
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Municipal wastewaters are a complex mixture containing estrogens and estrogen mimics that are known to affect the reproductive health of wild fishes. Male fishes downstream of some wastewater outfalls produce vitellogenin (VTG) (a protein normally synthesized by females during oocyte maturation) and early-stage eggs in their testes, and this feminization has been attributed to the presence of estrogenic substances such as natural estrogens [estrone or 17β-estradiol (E2)], the synthetic estrogen used in birth-control pills [17α-ethynylestradiol (EE2)], or weaker estrogen mimics such as nonylphenol in the water. Despite widespread evidence that male fishes are being feminized, it is not known whether these low-level, chronic exposures adversely impact the sustainability of wild populations. We conducted a 7-year, whole-lake experiment at the Experimental Lakes Area (ELA) in northwestern Ontario, Canada, and showed that chronic exposure of fathead minnow (Pimephales promelas) to low concentrations (5–6 ng·L⁻¹) of the potent 17α-ethynylestradiol led to feminization of males through the production of vitellogenin mRNA and protein, impacts on gonadal development as evidenced by intersex in males and altered oogenesis in females, and, ultimately, a near extinction of this species from the lake. Our observations demonstrate that the concentrations of estrogens and their mimics observed in freshwaters can impact the sustainability of wild fish populations. • endocrine disrupters • fathead minnow • municipal wastewaters • population • level effects • whole-lake experiment
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Sexual differentiation in fish occurs after hatching during early life-stages and is believed to be a time when the gonad has a heightened sensitivity to disruption by chemicals that mimic hormones. In this study fathead minnows (Pimephales promelas) were exposed to an environmentally relevant concentration of ethinylestradiol (EE2) for short intervals in fish early life-stages and vitellogenic and gonadal responses were measured at 30 and 100 dph (sexual maturity), respectively. All EE2 exposure regimes induced vitellogenin (VTG) synthesis and disruption in duct development (a feminization) in males, with a window of enhanced sensitivity between 10 and 15 dph (where 60% of the males had feminized ducts). There was an altered pattern in sex cell development in males (inhibition of spermatogenesis) in the solvent controls (ethanol 0.1 ml/l) and all EE2 treatments when compared with the dilution water controls. Furthermore, fewer spermatozoa were observed in the testis of males exposed to EE2 from 15 to 20 dph and fertilized eggs (<24 h post-fertilization)-20 dph, compared with both the solvent and dilution water controls. These data show that short exposures of embryos/very early life-stage fathead minnows to an environmentally relevant concentration of EE2 lead to alterations in gonadal development that potentially have reproductive consequences and thus population level effects.
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Stable isotopes (δ¹⁵N and δ¹³C) were used to assess the changes in exposure and assimilation of sewage-derived nutrients in an aquatic food web following changes in effluent quality over an 8 year period at two municipal wastewater treatment plants (WWTPs) that discharge to the Grand River, in southern Ontario. Upgrades at the Kitchener WWTP started in late 2012 to enhance nitrification, while the Waterloo WWTP had a series of construction issues at the plant that resulted in a deterioration of its effluent quality over the study period (2007–2014). Fish (rainbow darter, Etheostoma caeruleum) and primary consumers (benthic invertebrates) were sampled in the receiving waters associated with each outfall. Upgrades at the Kitchener WWTP resulted in improved effluent quality with total annual ammonia output dropping by nearly sixfold (583–100 t), while the Waterloo WWTP increased its total annual ammonia output by nearly fourfold (135–500 t) over the duration of the study. Downstream of the Kitchener WWTP, the reduction in total ammonia output negatively correlated with changes in δ¹⁵N of rainbow darter from being depleted (prior to the upgrade) to reflecting signatures similar to those at the upstream reference site. The biota downstream of the Waterloo WWTP showed the opposite trend, going from slightly enriched, to being depleted relative to the upstream reference sites. δ¹³C was consistently higher downstream of both WWTPs regardless of changing effluent quality, and annual variability in δ¹³C was associated with annual river discharge. In a laboratory based dietary switch study conducted with rainbow darter, the isotope half-life in muscle (29 days for δ¹⁵N and 33 days for δ¹³C) were determined and these rapid changes were consistent with responses in muscle of wild fish. This is a unique study that was able to contrast two WWTPs in the same watershed as they underwent major changes in treatment processes. Stable isotopes were very effective as a tool to trace the changes in aquatic biota due to changes in wastewater effluent quality, both improvements and deterioration over time.
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http://authors.elsevier.com/a/1SkJy,3oDQUqU2 Exposure of wildlife to endocrine disrupting chemicals (EDCs) is not necessarily continuous. Due to seasonal changes and variable industrial and agricultural activities it often occurs intermittently. Thus, it is possible that aquatic organisms may be more affected by periodic peak exposure than by chronic exposure. Therefore, an experimental scenario including an exposure from 2 hours to 90 days post-fertilization (dpf) and a subsequent recovery period until 150 dpf was chosen to assess the potential reversibility of the effects of sex steroids on sexual and gonad development of zebrafish (Danio rerio). The aim of this study was to investigate the persistence of the endocrine effects of an estrogen (EE2-17α-ethinylestradiol, 4 ng/L), an inhibitor of estrogen synthesis (Fad-fadrozole, 50 μg/L) or their binary mixture (Mix-EE2+ Fad, 4 ng/L + 50 μg/L). Afterwards, a semi-quantitative histological assessment was used to investigate histopathological changes on gonad differentiation and development. The data showed that fadrozole, alone or in combination with EE2, permanently disrupts the sexual development, inducing masculinization and causing severe pathological alterations in testis, such as intersex associated to the enlargement of sperm ducts, interstitial changes, asynchronous development and detachment of basal membrane. After exposures to both EDCs and their mixture, the gonad histopathology revealed interstitial proteinaceous fluid deposits and, in ovaries, there were atretic oocytes, and presumably degenerative mineralization. On the other hand, the gonadal changes induced by EE2 alone seem to be partially reversible when the exposure regime changed to a recovery period. In addition, EE2 enhanced zebrafish growth in both genders, with male fish presenting signs of early obesity such as the presence of adipocytes in testis. Moreover, sex ratio was slightly skewed toward females, at 90 and 105 dpf, in zebrafish exposed to EE2. The data further indicate that long-term studies on impacts of single EDCs and their mixtures with recovery periods are crucial to reveal the possibility of sex reversal and pathological changes of gonads that can adversely affect breeding.
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Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
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Municipal wastewater effluents (MWWEs) contain anthropogenic substances that can exhibit endocrine-disrupting activity. These complex mixtures have been observed to exert adverse effects on fish. Rainbow darter (Etheostoma caeruleum, RBD) is a small benthic fish that is widespread throughout the Grand River, Ontario, Canada, and has been previously shown to be adversely affected by MWWE exposure in this watershed. The objectives of this study were to quantify biological responses in this sentinel species and intersex severity in male fish, in relation to the area of urbanization. It focused on RBD populations adjacent to wastewater outfalls in the Grand River watershed. In May 2011, nine sites across the urban gradient were selected to evaluate the impact of MWWEs. Endpoints for energy storage (i.e. condition factor, k; liversomatic index, LSI) as well as reproductive endpoints (i.e. gonadosomatic index, GSI; gonad development, hormone production), and intersex were assessed in the fish. Rainbow darter showed a high incidence of intersex downstream of the wastewater outfalls, especially below the largest treatment plant outfall at Kitchener (∼85%). We applied an intersex index (score from 0 to 7) that considers the number of eggs within the testis and the stage of maturation of the egg. RBD exposed downstream of the largest wastewater outfall at Kitchener had a score of 3.81±0.37 compared to upstream to the urban areas where there were no intersex males found other than a single individual with a score 1 (average intersex score of site 0.06±0.06). In addition, several fish associated with the Kitchener outfall had macroscopic vitellogenic eggs in the testes (intersex scores 5 and 6). The sub-population of fish located at the wastewater outfall also showed a tendency towards skewed sex ratios (greater proportion of females to male fish) compared to the population at the reference sites. Male fish inhabiting the urbanized area of the Grand River also showed reduced levels of testosterone (T) and 11-ketotestosterone (11KT). Intersex males had the lower levels of 11KT relative to the upstream reference fish but could not be distinguished from normal males collected at the exposed sites. Despite the high levels of intersex at these sites, no relationships were evident among intersex severity and other measured endpoints such as GSI, LSI or in vitro steroid production. The effects observed appear to be associated with urbanization and exposure to treated MWWEs in the watershed. Although intersex incidence and severity was a very good indicator of wastewater exposure, intersex could not be directly linked to other effects in this wild population. The effects of MWWEs on transcriptional changes in adult RBD exposed to the effluents are reported in the corresponding report (Part B). Copyright © 2014 Elsevier B.V. All rights reserved.